Colin Russell is a fictional character from the BBC soap opera EastEnders, played by Michael Cashman. The character appears between 5 August 1986 and 23 February 1989 and on 8 and 9 September 2016. Colin is originally portrayed as a middle-class yuppie with a kind heart. The character is Walford's first on-screen gay resident and he featured in the UK's first homosexual kiss on a soap opera, which caused controversy in the British press. Cashman reprised the role of Colin for the funeral of Dot Cotton (June Brown) for two episodes broadcast on 12 and 13 December 2022.

Colin is EastEnders' first homosexual character. Introduced in August 1986, Colin was one of the more popular characters in the early years of the programme. At first the audience and the residents of Walford were kept in the dark about the fact that Colin was gay. This changed by the end of the year, at which time Colin acquired a young boyfriend named Barry Clark (Gary Hailes).

Colin was one of the most controversial characters of his time — mainly because gay-orientated content was still relatively rare on prime-time television during the mid-1980s. Gay characters that existed were usually farcical, camp parodies, created purely for comic relief, such as Mr Humphries in the situation comedy, Are You Being Served? Although EastEnders was not the first UK televised soap to include a gay character (Channel 4's Brookside had that accolade), the portrayal of an openly gay male, let alone a homosexual relationship, on a prime-time, pre-watershed BBC programme was unheard of before Colin and Barry's introduction. The licence funded BBC held a far greater audience share than the commercially funded Channel 4, thus public reaction to EastEnders' gay characters was much stronger and more widely documented in the British press.

Colin was a middle-class, well-meaning, slightly uptight yuppie, and his inclusion was an attempt to portray the gentrification of the East End of London. The openly gay actor and gay activist Michael Cashman, who had roots in the East End, was chosen to play the role. Cashman initially resisted playing Colin, but was persuaded by his boyfriend, Paul Cottingham, and after receiving his parents' backing, he accepted the part. During his audition, Cashman was not aware of his character's sexual orientation.

The makers of EastEnders decided that Colin's partner needed to be in stark contrast in order to prevent Colin from becoming too rarefied (up until this point middle-classed characters had been relatively unsuccessful and had failed to fully integrate into EastEnders predominantly working-class community). Barry was scripted to be much more down-to-earth in comparison: working-class instead of middle-class; openly gay instead of 'in the closet'; loud and brash instead of shy and retiring, and in addition the age difference between the two was substantial — Colin being roughly fifteen years Barry's senior.

A relationship between Colin and Barry was quickly developed and the residents of Albert Square gossiped in hushed voices about the true nature of their friendship. In 1987 EastEnders was responsible for screening the first ever gay kiss in a UK soap opera, much to the outrage of the viewing public. A small kiss on the forehead, given to Barry from Colin, received a record number of complaints from angry viewers. In addition, the right-wing British press reacted with fury. They began a smear campaign, branding the programme 'filth' and, for a while, dubbed the show EastBenders. There were even questions in parliament about whether it was appropriate to have gay men in a family show when AIDS was sweeping the country.

Despite the initial negativity, the storyline had a powerful impact on public attitudes and the show's handling of Colin and Barry's relationship was deemed by many gay activists as something of a breakthrough. Not only did EastEnders brave the wrath of many moralistic viewers and bigoted journalists, but they also exposed that bigotry through the characters in the show — most notably via the inane naivety of local gossip Dot Cotton (June Brown), who erupted into horror and ignorant self-righteousness upon discovering Colin and Barry's secret, and even spread rumours that Colin had AIDS. The episode featuring the kiss was watched by over 17 million viewers, and Colin and Barry remained on-screen for several years, accessing millions of viewers each episode — the gay community were finally being represented on mass audience mainstream television. Gradually, negative assumptions began to lessen, public opinion began to shift in Colin and Barry's favour and even Dot got used to the idea of having gay neighbours. Michael Cashman has commented: "This was a flagship BBC show, the most popular series in the country, and Colin and Barry were there day in, day out. The relationship wasn't sensationalised, and the public devoured it." The importance of Colin was so great in the gay community at the time that Cashman was asked to lead a march against Section 28, which prohibited local authorities from promoting homosexuality or the acceptability of homosexuality.

Barry and Colin remained an on-screen couple until the end of 1987. Their characters were used to highlight many other gay issues, such as homophobia, gay bashing and gay legal inequality — i.e. the legal age of gay sexual consent (which at the time was 21 instead of 16 as it is today). Eventually, the differences between Colin and Barry became too great for them to overcome, they split and Barry left Walford for a job on a cruise ship.