George Galloway has been branded a "laughing stock" by a Labour opponent after the Respect MP imitated a cat on Celebrity Big Brother.
Mr Galloway lapped imaginary cream on television
Mr Galloway, 51, went on all fours, purred and pretended to lick cream from actress Rula Lenska's hands, as part of a task set on the Channel 4 show.
Labour London Assembly member John Biggs accused the Bethnal Green and Bow MP of neglecting his constituents.
But Mr Galloway says taking part in the programme is good for politics.
He missed a Commons vote on London's Crossrail project, which would run through his constituency, on Thursday.
Mr Biggs, City and East member on the assembly, said: "His antics on TV, just hours after missing a crucial parliamentary vote affecting his constituency, demonstrate that he is becoming one of the biggest laughing stocks in London politics since the Second World War."
During a Big Brother task to see whether "humans can communicate with animals", Mr Galloway asked Ms Lenska: "Now, would you like me to be the cat?"
He crawled on all fours and then pretended to lap from her hands as if drinking cream, after which she rubbed the "cream" from his "whiskers" and stroked his head and behind his ears.
Earlier, Mr Galloway acted the role of "lab assistant" while Ms Lenska "read the mind" of a goldfish called Barry.
Labour Chief Whip Hilary Armstrong has launched a petition against Mr Galloway.
It urges him to "represent and respect his constituents, not further his own ego, as he is by remaining totally out of touch in the Big Brother house".
Ms Armstrong said of the "cat" act: "It made me cringe. I'm absolutely bemused that he decided to do something where he is uncontactable by the people he represents or works for.
"Something serious could happen here today and no-one can contact him, he could not say or do anything - and that to me seems a bit strange for someone who is, and has wanted to be, a publicly elected official."
But Mr Galloway's spokesman said earlier this week that the constituency office was open as normal.
"It is his hope that Big Brother would provide the kind of platform that the media does not normally provide for him," he added.
"He is coming across as a human being, while the press have tried to demonise him in the past."
Lib Dem Northern Ireland spokesman Lembit Opik said politicians had to "connect" with the public.
He added: "We need to lighten up a little bit. George Galloway won't be the next leader of the Labour Party."
Respect is sending a letter of complaint to Channel 4 claiming Mr Galloway's conversations with other housemates about the Iraq war and other political issues have not been shown.
Peter Bazalgette, UK chairman of programme makers Endemol, told BBC One's This Week that Channel 4 had to abide by strict rules on broadcasting political opinions without opposing views to balance them.
He said producers were considering staging a political debate in the house to allow Mr Galloway to speak more freely.