London Mayor Boris Johnson has rejected claims that his 2012 decision to ban anti-gay adverts on the capital’s buses was in order to gain votes and says it was right of his staff to notify The Guardian newspaper.

The Court of Appeal last week ruled a probe is needed to consider whether the mayor acted “for an improper purpose”.

The charity, the Core Issues Trust, believe that Boris Johnson abused his position as Mayor of London in having the adverts pulled in order to “secure the gay vote”.

Lord Dyson, the second most senior judge in England and Wales, criticised the decision-making process by the office of the Mayor of London.

The judge said evidence had been produced of “an email which unequivocally states that the mayor ‘instructed’ Transport for London [TfL] to pull the advertisement,” just before London went to the polls.

Appearing for his monthly ‘Ask Boris’ programme on LBC 97.3 on Tuesday, Mr Johnson rejected claims the adverts were pulled in order to gain votes.

“No. I did it… I decided that the thing should obviously come off the buses because it was totally offensive. And actually the important point is that even before I had taken that action and made my views very plain to TfL as you would expect me to do – and I’m sure Londoners would expect me to do – [TfL] had already got it and had done it.

“And you have got to remember this was an evening I think in the spring of 2012. And the [phone] lines went red hot at TfL and they knocked it off… they decided to whack it immediately.”

When asked by LBC presenter Nick Ferrari, “why was it necessary for someone in your office to contact The Guardian about this?” Mr Johnson replied: “Because we were getting lots of calls about it as far as I can remember and people wanted to know what my view was and I took a very clear view”.

Mr Ferrari interrupted: “So you tell The Guardian do you?” Mr Johnson replied: “Well I didn’t tell The Guardian, somebody told them and quite right too. [If] The Guardian is going to ask what my view is it seems only reasonable for us to tell them in the spirit of transparency, clarity and all the rest of it.”

Mr Ferrari said: “You don’t put out a statement or a press release, you ring The Guardian newspaper to let them know?”

Mr Johnson replied: “I think to be fair I think it was The Guardian who were making inquires,” breaking into a laugh he adds, “What do you want to do? not answer questions from the media?”

Mr Ferrari said: “No I love it when you answer questions from the media, I’m very grateful when you do. But I just wonder why… so it was The Guardian who had started the story?”

The mayor replied: “Yes. I think it was The Guardian… this wasn’t coming to us from TfL it was coming to us from the media.”

When asked if the actions could be seen to produce “political capital”, Mr Johnson said: “Let’s be very clear, I didn’t think it was the right thing for London to have [a] sort of homophobic bus advertisement situation… so I didn’t want homophobic buses, or however you want to express it, on the streets of London and that was my view and I expressed it very clearly to TfL.

“As it happened it was a bit like Murder on the Orient Express, in the sense that by the time I came to plunge the dagger into the homophobic bus it was already dead so there you go.”