Transport for London tells Channel 4 News it banned an advert which suggests gay people can be converted to heterosexuality because it was "offensive".

The advert - "Not gay! Post-gay, ex-gay and proud. Get over it!" - which had been booked to run on five central London bus routes, was proposed by religious groups Core Issues Trust, an Anglican Christian organisation which assists churches "for ministering to those who have issues of homosexuality", and Anglican Mainstream, a global orthodox Anglican group.

The advert uses the same typeface and black and white lettering on a red background as the current Stonewall campaign, pictured above, which reads "Some people are gay. Get over it!"

Stonewall's advertising campaign was launched to promote equal marriage, and has been carried by 1,000 London buses.

The controversial adverts were pulled days before the posters were due to be pasted on to London's buses. Labour mayoral candidate Ken Livingstone said the adverts should never have been booked in the first place, but a spokesperson for Transport for London (TFL) said they had only just been brought to its attention by TFL's advertising agency, CBS Outdoor.

'Offensive'

While CBS Outdoor felt the adverts were acceptable, TFL found they had breached two clauses of their advertising code: firstly that it was "likely to cause widespread or serious offence to members of the public" and secondly that it contained "messages which relate to matters of public controversy and sensitivity".

TFL's spokesperson told Channel 4 News: "We have an advertising code over what we are comfortable with. In this case we felt it would be offensive to parts of our customer base."

"We have decided that it should not run on London's bus or transport networks. We do not believe that these specific ads are consistent with TFL's commitment to a tolerant and inclusive London."