DS Collins—described by The Guardian's Hollie Richardson as "a heavy-sighing, perma-frown primetime detective" and an "outlier and an outsider"—is a Detective Sergeant from the Directorate of Special Investigations. The Telegraph suggested that she displayed a "rigid attention to detail at work that masks a sadness in her personal life, which seems to be represented by a signature anorak that is the colour of a dying autumn leaf". Ed Cumming of The Independent, summarises her as "a single, gay, childless cop: it’s made to look like a thankless gig".⁸

PC Lizzie Adama is a newly qualified rookie, having been in the MPS for six months. Constable Matthews, a veteran cop of the old school, aspires to become a police training officer. He is only seen in flashbacks. Kieran Shaw is Adama's and Matthews' immediate superior and has been engaging in an extramarital affair with the former. His relationship with the DSI team becomes increasingly fractious, and Collins suspects him of knowing far more about Adama's disappearance than he is letting on. However, he is protected by his superior, DCI Tim Baillie, until the last episode in the series.

The show was commissioned by ITV and produced in three 50-minute episodes by Mammoth Screens—a subsidiary of ITV—and Windhover Films, owned by Harbinson. It was produced and edited by Paul Testar and Gez Morris respectively. Several different scenarists were considered before Patrick Harbinson, who had previously co-produced the Showtime series Homeland, was chosen as both writer and executive producer. It was directed by Jim Loach and developed for television by Sly Fox Productions. In describing the premise of the first series, Harbinson said:

It's a story of a typical London street – two families living cheek by jowl – one English white and middle-class, the other Libyan refugees, just settled in the community after two years of limbo in hostels and refugee camps. A dispute arises between them, basically out of nothing, and then escalates. And it's also the story of a typical London police station, whose officers have to deal with that dispute.

The COVID-19 pandemic prevented Harbinson from doing the usual thorough location searches, and he had to rely on images being Dropboxxed to him from around the country. Although set in southeast London, The Tower was predominantly filmed in northwest England, with a week spent in London during post-production doing pick-up shots, particularly of the City of London skyline. Northern locations included Liverpool, Manchester, Runcorn, Warrington and Knutsford's Tatton Park. Sharif later recalled the scenes filmed in Liverpool as particularly difficult due to pervasive rain, which made her "emotional, heavy dialogue... challenging". The disused cellars of the Martins Bank Building in Liverpool were used to replicate the police cellblock.

Although the original book was published many years before the murder of Sarah Everard by serving Met officer Wayne Couzens, the show's timing made the comparison obvious to some critics. For example, Paul Kendall in The Telegraph placed the show squarely in the context of contemporary police–public relations, particularly in the aftermath of the Couzens case. The Guardian's Lucy Mangan considered the show's release timely, as "trust in officers is at an all-time low". She was generally positive about the first episode, writing that "the plot builds at pace but without inducing vertigo in the viewer" and noting its background of "racial tensions, bigger crimes, personal secrets and political arse-covering". Writing in The Times, Carol Midgley identified an "aura of grim authenticity", which she put down to the original author's police background. Although she noticed a Line of Duty–style "what are all these coppers hiding?" trope, she considered the show to have successfully avoided the tendency to focus on the murder of females.

However, Midgely criticised the sound engineering. She complained that, at times, it was difficult to hear; "was it just my old ears or were the actors going for a mumbling level worthy of The Wire?" A similar criticism, of muffled—and also hurried—dialogue was made by Digital Spy, who argued that this was a common refrain from viewers on Twitter. Anita Singh of The Telegraph also criticised dialogue which sounded as if some cast members were "mumbling at their shoes". She summed up the series, effectively, as "everyone is lying about what happened and Collins is here to find out why", although she disagreed that the series was derivative of Line of Duty: while the DSI might appear to be another A10, she suggested The Tower had a greater sense of day-to-day realism than similar programmes. Also addressing comparisons with Line of Duty, Ed Cumming suggested that, unlike that show, with The Tower "there isn't much pure evil here, more opportunists and easy-life seekers". He also argued that, thanks to Loach's direction, The Tower was a tighter script—with less "flabbiness"—than many of its genre. However, he was overall critical, arguing that Whelan is the only character to consistently hold the viewers' interest and that, generally, the series could have "aimed a bit higher". The Guardian's Barbara Ellen was also less enthusiastic, picking out what she considered an overuse of flashbacks adding unnecessary confusion to an already complex plot, combined with the shoehorning in of too many themes. She was more positive of the dialogue and portrayals, summing up saying "bring back the characters, please, but with a less chaotic story".

Tahirah Sharif believed that there was plenty of material to allow for the series' expansion, and Emmett Scanlan has pointed out that the later books expand the characters also, particularly Bradshaw's.

A third series of The Tower was announced in July 2023, entitled The Tower: Gallowstree Lane and based on the novel of the same name by London. It focuses on DI Shaw's character, and a scandal that plagues his efforts to topple an organized crime ring. Whelan and Sharif are confirmed to return as their characters, who will be working side by side.

Kate London was born in Staffordshire to a retired RAF sergeant and a nurse. A graduate of the University of Cambridge, she took up acting and played alongside Hugh Bonneville and Dominic Dromgoole. She travelled to Paris and attended the same clown school as Sacha Baron Cohen would later. She joined the Metropolitan Police Service (MPS) as a uniformed PC in 2006 and left in 2014 as a murder squad detective in a Homicide and Serious Crime Command dealing with major investigations before becoming a full-time author. She also writes regularly for newspapers. In response to comparisons between The Tower and the murder of Sarah Everard in March 2021, London argued that, in a close-knit institution such as the police, officers often do not speak out or criticise, through fear of becoming known as a troublemaker. London notes that, in the universe of The Tower, this is at the root of the police's problem, and by extension the public's:

In The Tower, people don’t speak up, they don’t say "No", and we know historically, in any place where bad things are happening, good people need to speak up, and when they don’t, catastrophe ensues. The Tower is a story. Saying all police are like the police in The Tower is like saying all kings are like Lear. But there do need to be things in place to make it easier for people to speak out and do the right thing.

London lives and writes in Shropshire. Critic Joan Smith positively reviewed Post Mortem on its 2015 publication, arguing that London "vividly recreates the everyday experience of uniformed police, for the most part avoiding the temptation to take sides. The result is a complex novel that offers rare insights into how the police operate." London was nervous of ITV's proposal to televise Post Mortem as she had experienced two previous, unsuccessful attempts at turning her book into script.

• The Tower at IMDb