David Christopher Kelly CMG (14 May 1944 – 17 July 2003) was a Welsh scientist and authority on biological warfare (BW). A former head of the Defence Microbiology Division working at Porton Down, Kelly was part of a joint US-UK team that inspected civilian biotechnology facilities in Russia in the early 1990s and concluded they were running a covert and illegal BW programme. He was appointed to the United Nations Special Commission (UNSCOM) in 1991 as one of its chief weapons inspectors in Iraq and led ten of the organisation's missions between May 1991 and December 1998. He also worked with UNSCOM's successor, the United Nations Monitoring, Verification and Inspection Commission (UNMOVIC) and led several of their missions into Iraq. During his time with UNMOVIC he was key in uncovering the anthrax production programme at the Salman Pak facility, and a BW programme run at Al Hakum.

A year after the publication of the 2002 dossier on Iraqi weapons of mass destruction—which stated that some of Iraq's chemical and biological weapons were deployable within 45 minutes—Kelly had an off-the-record conversation with Andrew Gilligan, a BBC journalist, about the claim. When Gilligan reported this on BBC Radio 4's Today programme, he stated that the "45 minutes" claim was included at the insistence of Alastair Campbell, the Downing Street Director of Communications; Kelly denied that he said Campbell had forced in the reference. The government complained to the BBC about the claim, but they refused to recant on it; political tumult between Downing Street and the BBC developed. Kelly informed his line managers in the Ministry of Defence that he might have been the source, but did not think he was the only one, as Gilligan had reported points he had not mentioned. Kelly's name became known to the media, and he was called to appear on 15 July before the parliamentary Intelligence and Security and Foreign Affairs select committees. Two days later Kelly was found dead near his home, having killed himself.

Following Kelly's suicide Tony Blair, the Prime Minister, set up a government inquiry under Lord Hutton, a former Lord Chief Justice of Northern Ireland. The inquiry concluded that Kelly had killed himself. Hutton also stated that no other parties were involved in Kelly's death. There was continued debate over the manner of Kelly's death, and the case was reviewed between 2010 and 2011 by Dominic Grieve, the Attorney General; he concluded that there was "overwhelmingly strong" evidence that Kelly had killed himself. The post-mortem and toxicology reports were released in 2010; both documents supported the conclusion of the Hutton Inquiry. The manner of Kelly's death has been the subject of several documentaries and has been fictionalised on television, on stage and in print. He was appointed as Companion of the Order of St Michael and St George (CMG) in 1994 and might well have been under consideration for a knighthood in May 2003, according to Hutton. His work in Iraq earned him a nomination for the Nobel Peace Prize.

David Christopher Kelly was born in Llwynypia, Glamorgan, South Wales, on 14 May 1944. His parents were Thomas John Kelly and Margaret, née Williams; Thomas was a schoolteacher who was serving in the Royal Air Force Volunteer Reserve as a signals officer during the Second World War. Thomas and Margaret divorced in 1951; she took their young son and moved in with her parents in Pontypridd. From the age of eleven he attended the local grammar school. He was a keen sportsman and musician at school, and represented Wales in the youth cross-country running team; he played double bass in the National Youth Orchestra of Wales and played the saxophone to a high standard.

In 1963 Kelly was admitted to the University of Leeds to study chemistry, botany and biophysics. His mother died two years later from an overdose of prescription barbiturates. Although the coroner's inquest gave an open verdict, Kelly believed she had killed herself. As a result of the death, Kelly suffered from insomnia and was prescribed sleeping pills; he was also given an extra year to complete his degree. He graduated in 1967 with a BSc in bacteriology; he then obtained an MSc in virology from the University of Birmingham. Between his first and second degrees, on 15 July 1967, he married Janice, née Vawdrey, who was studying at Bingley Teacher Training College.

Kelly joined the Insect Pathology Unit at the University of Oxford in 1968, while a student of Linacre College. In 1971 he received his doctorate in microbiology; his thesis was "The Replication of Some Iridescent Viruses in Cell Cultures". In the early 1970s he undertook postdoctoral research at the University of Warwick, before moving back to Oxford in the mid-1970s to work at the Institute of Virology and Environmental Microbiology. There he carried out virology research into pests such as Spodoptera and Aedes. He rose to the position of Chief Scientific Officer; much of his work was in the field of insect viruses.

In 1984 Kelly joined the Ministry of Defence (MoD) as the head of the Defence Microbiology Division working at Porton Down, Wiltshire. The department had only a small number of microbiologists when he arrived, and most of their work involved the decontamination of Gruinard Island, which had been used during the Second World War for experiments with weaponised anthrax. He increased the scope of his department, obtaining additional funding to undertake research into biodefence. Because of the work undertaken by Kelly and his team, the UK were able to deploy a biodefence capability during the 1990–1991 Gulf War.

In 1989 Vladimir Pasechnik, the senior Soviet biologist and bioweapons developer, defected to the UK and provided intelligence about the clandestine biological warfare (BW) programme, Biopreparat. The programme was in contravention of the 1972 Biological Weapons Convention which banned the production of chemical and biological weapons. Pasechnik was debriefed by the Defence Intelligence Staff (DIS), who requested technical assistance to process the information on chemical and biological matters; Kelly was seconded to the DIS to assist with his colleagues Brian Jones and Christopher Davis. They debriefed Pasechnik over a period of three years.

Kelly undertook several visits to Russia between 1991 and 1994 as the co-lead of a team from the UK and US which inspected civilian biotechnology facilities in Russia. One of the restrictions placed on the inspectors was that visits could only be to non-military installations, so, for the first visit in January 1991, the team visited the Institute of Engineering Immunology, in Lyubuchany; the State Research Centre for Applied Microbiology in Obolensk; the Vector State Research Center of Virology and Biotechnology in Koltsovo; and the Institute of Ultrapure Preparations, in Leningrad (now Saint Petersburg). The Russians obstructed the team and tried to stop inspection of key areas of the facilities; they also lied about the use to which parts of the installations were put. On one visit to the Vector facility, Kelly had a conversation with a laboratory assistant—one who was too low grade to have been fully briefed by the KGB. Kelly asked the assistant about the work he was doing, and was surprised when the man said he was involved in testing smallpox. Kelly questioned Lev Sandakchiev, the head of Vector, about the use of smallpox, but received no answers. Kelly described the questioning sessions as "a very tense moment".

In a 2002 review of the verification process, Kelly wrote:

The visits did not go without incident. At Obolensk, access to parts of the main research facility—notably the dynamic aerosol test chambers and the plague research laboratories—was denied on the spurious grounds of quarantine requirements. Skirmishes occurred over access to an explosive aerosol chamber because the officials knew that closer examination would reveal damning evidence of offensive BW activities. At Koltsova access was again difficult and problematic. The most serious incident was when senior officials contradicted an admission by technical staff that research on smallpox was being conducted there. The officials were unable to properly account for the presence of smallpox and for the research being undertaken in a dynamic aerosol test chamber on orthopoxvirus, which was capable of explosive dispersal. At the Institute of Ultrapure Preparations in Leningrad (Pasechnik's former workplace), dynamic and explosive test chambers were passed off as being for agricultural projects, contained milling machines were described as being for the grinding of salt, and studies on plague, especially production of the agent, were misrepresented. Candid and credible accounts of many of the activities at these facilities were not provided.

Two official reports of the visit concluded that Soviets were running a covert and illegal BW programme. Kelly also took part in reciprocal visits to the United States Army Medical Research Institute of Infectious Diseases at Fort Detrick, Maryland, and visits to Porton Down by Russian and American inspectors. Despite their findings, Kelly concluded that the tripartite inspection programme had failed. It was, he said, "too ambitious; its disarmament objective deflected by issues of reciprocity and access to sites outside the territories of the three parties". He went on to add that "Russia's refusal to provide a complete account of its past and current BW activity and the inability of the American–British teams to gain access to Soviet/Russian military industrial facilities were significant contributory factors".

Following the end of the Gulf War, United Nations Security Council Resolution 687 imposed the articles of Iraq's surrender. The document stated "that Iraq shall unconditionally accept the destruction, removal, or rendering harmless, under international supervision, of ... All chemical and biological weapons". This was to be made possible by "The forming of a special commission which shall carry out immediate on-site inspection of Iraq's biological, chemical and missile capabilities, based on Iraq's declarations and the designation of any additional locations by the special commission itself". The group set up was the United Nations Special Commission (UNSCOM), and Kelly was appointed to it in 1991 as one of its chief weapons inspectors in Iraq. The Iraqis had provided Rolf Ekéus, the director of UNSCOM, with a list of sites connected with the research and production of weapons of mass destruction (WMD) in the country, about half of which had been bombed during Operation Desert Storm. These sites provided the starting point for the investigations. In August 1991 Kelly led the first group of UN BW investigators into the country. When asked where the inspection teams would visit, he told reporters "We will go to sites which we deem to have characteristics associated with biological activity, but at the moment ... I have an open mind." The first UNSCOM missions finished with no evidence found of an Iraqi biological or chemical programme, although they did establish that some sites suspected by US intelligence services of involvement in biological or chemical warfare research were legitimate. These included a bakery, a pharmaceutical research business in Samarra, a dairy and a slaughterhouse.

UNSCOM undertook 261 inspection missions to Iraq between May 1991 and December 1998, 74 of which were for biological weapons. Kelly led ten of the missions involved in BW inspections. In 1998 and 1999 Iraq refused to deal with UNSCOM or the inspectors; the country's President, Saddam Hussein, singled out Kelly by name for expulsion from the country. During an inspection mission to Iraq in 1998, Kelly worked alongside an American translator and US Air Force officer, Mai Pederson, who introduced him to the Baháʼí Faith. Kelly remained a member of the faith for the rest of his life, attending spiritual meetings near his home of Southmoor, Oxfordshire. He was, for a time, the treasurer of his local branch, based in Abingdon, Oxfordshire. His time in Iraq left him with a deep affection for the country, its people and culture, although he abhorred Saddam's government.

In 2000 UNSCOM was replaced by the United Nations Monitoring, Verification and Inspection Commission (UNMOVIC), whose mission and aims were similar to that of UNSCOM: to remove Iraqi WMDs and "to operate a system of ongoing monitoring and verification to check Iraq's compliance with its obligations not to reacquire the same weapons prohibited to it by the Security Council".

Kelly returned to work as a government advisor with the MoD on biological warfare, but also worked with UNMOVIC and continued to visit Iraq. He was involved in at least 36 missions to Iraq as part of UNSCOM and UNMOVIC, and, despite interference and obstruction tactics by the Iraqis, was instrumental in making the breakthrough to discover Iraq's BW facilities: the anthrax production programme at the Salman Pak facility and a BW programme run at Al Hakum.

In his 2002 State of the Union address, George W. Bush, the President of the United States, discussed the use of WMD by the Iraqi regime. Later that year he reaffirmed that "the stated policy of the United States is regime change". As part of the British government's arguments for war on Saddam, Tony Blair, the British Prime Minister, instructed the publication of a dossier on Iraqi WMD on 24 September 2002. The dossier, which was "based, in large part, on the work of the Joint Intelligence Committee (JIC)", included the statement that the Iraqi government had:

• continued to produce chemical and biological agents;
• military plans for the use of chemical and biological weapons, including against its own Shia population. Some of these weapons are deployable within 45 minutes of an order to use them;
• command and control arrangements in place to use chemical and biological weapons. Authority ultimately resides with Saddam Hussein.

Before its publication, Kelly had been shown a draft copy of the dossier and took part in a meeting at the DIS to review it. Four pages of comments were made regarding the information in the report, of which Kelly contributed twelve individual statements. The observations from the DIS were passed up to the Joint Intelligence Organisation; none of the observations referred to the 45-minute claim.

On 8 November 2002 the UN Security Council passed Resolution 1441, "a final opportunity to comply with its disarmament obligations under relevant resolutions of the Council; and accordingly decides to set up an enhanced inspection regime with the aim of bringing to full and verified completion the disarmament process". The resolution stated that the Iraqi government needed to provide full details of its WMD programme within 30 days. As a result of the increasing pressure on the Iraqi government, UNSCOM inspectors were readmitted to the country and were provided information on the Iraqi WMD programme. According to Kelly, despite the steps taken, Saddam "refuse[d] to acknowledge the extent of his chemical and biological weapons and associated military and industrial support organisations", and there was still a concern about "8,500 litres of anthrax VX, [sic] 2,160 kilograms of bacterial growth media, 360 tonnes of bulk chemical warfare agent, 6,500 chemical bombs and 30,000 munitions capable of delivering chemical and biological warfare agents [which] remained unaccounted for from activities up to 1991".

In February 2003 Colin Powell, the US Secretary of State, addressed the United Nations Security Council to discuss Iraq's WMD. He included information on mobile weapons laboratories, which he described as "trucks and train cars ... easily moved and ... designed to evade detection by inspectors. In a matter of months, they can produce a quantity of biological poison equal to the entire amount that Iraq claimed to have produced in the years prior to the Gulf War." Following his examination of the vehicles in question, Kelly spoke, off the record, to journalists from The Observer. In their article in the newspaper on 15 June 2003 they described him as "a British scientist and biological weapons expert", and quoted him as saying:

They are not mobile germ warfare laboratories. You could not use them for making biological weapons. They do not even look like them. They are exactly what the Iraqis said they were—facilities for the production of hydrogen gas to fill balloons.

One of the journalists who wrote the story, Peter Beaumont, confirmed to the Hutton Inquiry that Kelly was the source of this quote. Kelly was often approached by the press and would either clear the discussion with the press office of the FCO, or use his judgement before doing so; it was within his remit to liaise with the media. Shortly before the 2003 invasion of Iraq (20 March – 1 May 2003) Kelly anonymously wrote an article on the threat from Saddam which was never published. He outlined his thoughts on the build-up to war:

Iraq has spent the past 30 years building up an arsenal of weapons of mass destruction (WMD). Although the current threat presented by Iraq militarily is modest, both in terms of conventional and unconventional weapons, it has never given up its intent to develop and stockpile such weapons for both military and terrorist use.

He continued that "The long-term threat, however, remains Iraq's development to military maturity of weapons of mass destruction—something that only regime change will avert." On 20 March 2003 British and American troops entered Iraq to bring about the regime change. Most of the country was occupied and Saddam was overthrown within four weeks; Bush stated that war was over on 1 May 2003. On 7 May 2003 Kelly was telephoned by Susan Watts, the science editor of the BBC's Newsnight programme; the call lasted 15 to 20 minutes. They discussed various matters relating to Iraq including, towards the end of the conversation, the matter of the 45-minute claim. Watts's handwritten shorthand notes showed Kelly stated the claim was "a mistake to put in. Alastair Campbell seeing something in there, single source but not corroborated, sounded good." The pair also had a subsequent call on 12 May. Kelly flew to Kuwait on 19 May as part of a military team. He hoped to meet members of the Iraq Survey Group to see how the organisation worked. When he arrived in Kuwait he found that no visa had been arranged for him, so he returned home.