The Mayor of the American city of Portland has apologised for lying about a relationship he had in 2005 with an 18-year-old.

Sam Adams, 45, will leave the Inauguration ceremonies in Washington DC later today to return to the city to apologise to citizens for his dishonesty.

He took office on January 1st.

Both Mayor Adams and the teenager, Beau Breedlove, had lied about their relationship for 18 months, before Oregon newspaper Williamette Week broke the story.

They met in 2005 when Mr Breedlove was 17 but claimed they had a platonic friendship. At a meeting with reporters last week, the Mayor was presented with evidence of a sexual relationship, but again denied it.

Yesterday he told the Williamette Week that their relationship became sexual after Mr Breedlove turned 18 and continued for two months in the summer of 2005.

“I want to publicly acknowledge I made a mistake and apologise for it,” he told the paper.

“In the past, I’ve characterised my relationship with Beau Breedlove as purely non-sexual and that is not true.

“I should have been honest at the time when this first surfaced in 2007.

“But I didn’t believe that given the way that rumours were being spread—about whether I had broken the law by having sex with a minor—that people would believe me.

“Until today I have not discussed the true nature of the relationship with anyone. Not my friends, family, staff or colleagues on the council.

“I have apologised to Beau Breedlove for asking him to lie for me. I want to apologise to my colleagues for my dishonesty and especially to the people of Portland for my dishonesty.

“I should have been truthful from the beginning.”

Mayor Adams won 58% of the vote in spring 2008.

During the election campaign, his sexuality was not brought up by either himself or the opposition. He said:

“This is a testament to how fair-minded Portlanders are that it wasn’t an issue.

“I spend my time on the basic issues of life.

“A part of that includes equal rights, but that’s not even close to a majority of the time.

“Being gay is part of me, so is being Irish-American, so is being from a small Oregon town.”

Mayor Adams had previously been chief of staff to Mayor Vera Katz for 11 years, and a city councilor since 2004.