A Green MP campaigning against Page Three was told to cover up her slogan-branded T-shirt in Parliament yesterday.

Caroline Lucas, the MP for Brighton Pavilion, who has been campaigning for the famous feature of bare-chested women in The Sun to be banned, wore a T-shirt that read No More Page Three at the start of a commons debate on media sexism.

Jimmy Hood, chairman of the session, told her to comply with Westminster’s dress code and “put her jacket back on”.

Agreeing to put her jacket back on, she added it was “ironic” the T-shirt is inappropriate but “this kind of newspaper” is available in “eight different outlets on the Palace of Westminster estate”.

She added: “To date public pressure has secured the most public sign from The Sun’s proprietor that the paper might scrap Page Three.

“But the clock is ticking and we still have not seen any concrete action.

“So if Page Three still hasn’t been removed from The Sun by the end of this year I think we should be asking the Government to step in and legislate.”

The No More Page Three campaign, supported by Ms Lucas, was started by Lucy Holmes from Hove in September last year.

The 36-year-old posted a petition on the campaigning website change.org calling for the picture feature to be banned.

To date she has received more than 100,000 signatures of support.

She said: “With David Cameron and Nick Clegg responding to the No More Page Three campaign with patronising and naive comments like ‘shut the paper’ and 'if you don’t like it don’t buy it’, it is terrific that Caroline Lucas is standing up and speaking up about the gobsmacking sexism that we have had to put up with in the British press.

“People have had enough. They’ve had enough of a media that treats women as being primarily there for decoration and titillation, which sanctions calls of ‘get your tits out’ and seeks to silence those who speak up, like Clare Short did in the 1980s, with taunts of ‘you’re ugly and jealous’.”

A House of Commons spokesman said: “By convention members are expected not to use their clothing to display slogans or make debating points – members are expected to make their arguments through their speeches.”

Erskine May, the official Parliamentary rule book, says standards of dress for MPs is “expected to be adhered to as a matter of convention”.