Tom Quinn is a fictional character in the BBC espionage television series Spooks (called MI-5 in the United States), which follows the exploits of Section D, a counter-terrorism division of MI5.

[9] Throughout the first series, Tom engages in a relationship with Ellie Simm (Esther Hall), who knows him as "Matthew Archer", a civil servant in IT.

[1] In the second episode, Tom performed an undercover operation with fellow officer Helen Flynn (Lisa Faulkner) to recruit the wife of right-wing businessman, Robert Osbourne, who was believed to incite race riots throughout the country.

[12] Later in the second series, Tom starts a brief relationship with Vicky Westbrook (Natasha Little),[4] which he ends due to her behaviour after an EERIE (Extreme Emergency Response Initiative Exercise) in the fifth episode.

[13] In the following episode, Vicky retaliates by posting his phone number in Soho telephone boxes and clubs, garnering him unwanted attention.

While Tom has Sam Buxton (Shauna Macdonald) find and destroy every leaflet, CIA liaison Christine Dale (Megan Dodds) makes Vicky stop the harassment.

When it does not, Adam Carter (Rupert Penry-Jones) tracks down Joyce's wife and makes her confess to their plan to frame Tom, clearing him of all charges.

However, in the next episode, he undergoes a "conscience explosion" and sabotages an operation to lure a terrorist cell into buying "red mercury", because he did not like what was being done to the scientist in order for him to attempt to create it (which includes forging gambling debt, prompting the man's wife to leave him.

Tom briefly returns in the final episode, hired by Harry Pearce as an "outside contractor" to eliminate the head of a conspiracy of Russian nationalists who tried to derail the move to a closer Russian/UK relationship.

[12] Throughout the second series, Tom's "journey" has evolved slowly, where his attitude to his work has changed, and his conscience has "kicked in", finding himself questioning the world he is in.

"[21] Series creator David Wolstencroft believed that writing Tom was the most fun, yet the hardest work compared with other characters, because he was Spooks' primary protagonist.

[22] Wolstencroft chose a job in Information Technology (IT) as the cover story Tom used in his relationship with Ellie, because he felt that in real life people are reluctant to ask questions about IT work.

Howard Brenton, who wrote the series two finale, originally killed Tom off by drowning him while trying to escape onto the North Sea, while labouring under the impression that he was not to return.

in the cliffhanger of series two, was voted second in the "Favourite Moment" category in 2003, beaten only by the return of "Dirty Den" Watts in EastEnders.

Christopher Hootan of Metro opined "the return of Tom Quinn as a hired assassin in the final few seconds was a nice nod to early series of show.