Royal Air Force Holmpton or more simply RAF Holmpton is a former Royal Air Force Cold War era nuclear bunker that was built in the 1950s as an early warning radar station as part of the ROTOR Radar Defence Programme. Located just south of the village of Holmpton, in the East Riding of Yorkshire, England, RAF Holmpton remained a part of the Defence Estate right up to 8 December 2014 when it was sold into private ownership after 62 years of military service.

The site runs to about 36 acres (150,000 m) and comprises a number of surface structures along with a secure 35,000 square feet (3,300 m) command bunker which is about 100 feet (30 m) below ground.

The Bunker Design type R3-M2 (R3=Rotor Bunker Design M2=Including 2 additional mezzanine floors) was first built from 1951–3 and started life as an early warning radar station, part of the ROTOR programme. The bunker had originally been intended to be built at RAF Patrington, which was quite close, but the ground conditions at Patrington prevented this. An R3-M2 is a larger version of the standard UK R3 Bunker and RAF Holmpton was the only example of this type of structure in the UK as 1: It combined several Radar functions in the one building and 2: was a prototype for three similar bunkers built in Europe during the Cold War. The base covered 36 acres (15 ha) and the bunker is set in an excavation of about 100-foot (30 m). It is encased in 10-foot (3 m) of solid concrete all round with tungsten rods providing additional stability to the outer shell. The shell is then encased in brickwork and lined with pitch to form a waterproof membrane. Between the top of the bunker and the surface there is a concrete buster slab inserted to provide a deflection of any incoming ordnance. The bunker was created by one continuous pour of concrete and gravel which cost £1.5 million in 1953 (equivalent to £53,000,000 in 2023).

Between 1958 and 1975, the bunker site and RAF Holmpton and the domestic accommodation located further west at RAF Patrington, were known collectively as RAF Patrington. When the domestic site closed, the bunker site reverted to being called RAF Holmpton. In the late 1960s it became a Master Comprehensive Radar Station trialling the Ericsson 'Fire Brigade Auto Intercept Radar System', and later going on to house a massive Elliott & Plessey computer system for the 'Linesman Radar Project'. The 200 feet (61 m) tower (which weighted 200 tonnes (220 tons)), was dismantled in January 1971. All Radar functions at the site eventually closed in 1973 and for the next few years the site was used for training.

Between 1966 and 1974, a Meteor aircraft (WS788) was the gate guardian at Patrington. This was moved to RAF Leeming becoming the gate guardian there in the guise of one from No. 264 Sqn.

In the 1980s, the bunker was converted to form the new Emergency War Headquarters for RAF Support Command. However with the end of the Cold War in 1991 this function ceased and the site returned to training until 1994 when it was given a major refurbishment to become the first experimental (trialling) headquarters for the new UK Air CCIS system Electronic Warfare Advanced Communications System. This function remained at RAF Holmpton until 2002 although the CCIS Operations Room, known as AREA 7 remained intact until the end of July 2012.

Throughout its years as a Radar Station and through the years of Support Command & CCIS, the site also contained an operations area for the Royal Observer Corps (ROC) and although the Corps was 'stood down' in 1992 with some ROC units remaining as NBC cells until the end of 1995. This made RAF Holmpton one of the last places in the UK where any members of the Royal Observer Corps served and is a unique part of the site's history. In 1997 this project was abandoned and the site was then maintained under contract until 2003 by AQUMEN Defence. During this time it was used for occasional training by the RAF Regiment & the TA. In 2003 the site was leased for 25 years by the Ministry of Defence to RL(FRAFS)BLC Limited and the day-to-day management passed to HIPPO (The Holmpton Initiative Project Planning Office). By late 2003 plans were underway for a public exhibition on the site which opened to visitors in 2004.

In 2012 as a result of Government cutbacks and following a review of the Defence Estate the Ministry of Defence decided that the site was no longer required by the Air Force and the decision was made to terminate the lease and sell the whole site to RL(FRAFS)BLC who already held the original 25-year lease – During this period of transition the public visits continued to operate. The sale was completed in 2014. The last of the guided tours was held on 21 December 2014 and plans are now underway to close and completely refurbish the site during 2015 and Re-open it to public visits with a totally new visitor experience for Easter 2016 – The refurbishment has now been completed and the site reopened to visitors on 23 March 2016.

During the COVID-19 pandemic the bunker closed, but, in 2023 re-opened for occasional visits with some members of the original ROC volunteers on duty from time to time.

• RAF Holmpton - Visit The Bunker – official Facebook page
• Historic England Research Records: RAF Holmpton
• Imperial War Museum - Hidden: Cold War Women (Blog on staff who worked at RAF Holmpton)
• Hannah King (2018), The 'Moles' Who Served In A Secret Cold War Bunker, Forces.net; video (via YouTube)