Actors Andrew Lynford and Mark Homer both decided to leave the show after discussions with Executive Producer Matthew Robinson.

"They have mutually agreed that both characters have fulfilled their potential and will conclude their stories with a dramatic exit," said a spokeswoman for the series.

She added they will still be appearing in EastEnders until at least the spring.

The announcement comes days after Patsy Palmer - Bianca Butcher - revealed she was leaving to have a child.

Viewers this week saw barmaid Tiffany Mitchell - Simon's sister and Tony's ex-girlfriend - take a horrifying tumble down the stairs of the Queen Victoria in some of the last scenes Martine McCutcheon filmed before leaving.

Tony was caught between Simon and Polly (Victoria Gould)

The two characters were lovers for a while in 1997 - and the storyline broke taboos when bisexual Tony cheated on Simon with his fellow reporter at the Walford Gazette, Polly Becker.

The stormy relationship did not last, but the way the show portrayed Tony coming to terms with his bisexuality was widely praised.

Three out of the four mainstream soap operas have had gay characters in recent years. Anna Friel shot to fame through her portrayal of Beth Jordache in Brookside, while Emmerdale's vet Zoe Tate, played by Leah Bracknell, came out of the closet in 1993.

But now only Emmerdale is left - something lesbian and gay campaigning group Stonewall is unhappy about.

"Gay characters did seem to be on the rise for a while, but now they've got a bit of a low profile," said Stonewall spokesman Matt Aston.

"We'd like to see a few more positive role models in the media, especially to encourage young people who are coming to terms with their sexuality, as well as their friends and members of their family."

Anna Friel: Caused a stir as Beth in Brookside

Mr Aston praised EastEnders for the way it handled Tony's sexuality on screen. "It was very good for breaking what had been a taboo on prime-time television. It was a positive portrayal of how people can be confused about their sexuality.

"And as with any kind of exposure of these issues, people are made more aware of them and the problems people have with their sexuality. People also link them with us and get in touch to talk about it."

An EastEnders spokeswoman declined to say whether the programme would deal with more gay issues in the future.

The only mainstream soap which has not had any gay characters is Coronation Street.

Its producers say the show is not "issue-based" - but the programme has been praised for storylines involving transexual character Hayley Patterson.

Michael Cashman: Colin was EastEnders' first gay character

A decade has passed since EastEnders' first gay couple, Colin and Barry.

But homosexuality on TV is still a highly charged issue - Beth's infamous kiss with nanny Margaret in Brookside attracted both praise and criticism.

Channel 4 executive Jacquie Lawrence told the Edinburgh International Television Festival in August she wanted to see "gay consultants" advise drama producers.

"From British television, you wouldn't know what lesbians did in bed. You only ever see one woman," she said.

"The other one is so far off camera she might as well be down the paper shop buying The Guardian."