A key aide to Hammersmith MP Andy Slaughter has been forced to apologise after likening the Queen to a benefits scrounger on Twitter.

Matt Zarb-Cousin marked the Monarch's Diamond Jubilee by tweeting: "Congratulations this morning to Queen Elizabeth II. 60 years of scrounging benefits off the taxpayer without being caught."

The comment provoked an angry response from local Conservative politicians, including councillors Peter Graham, Harry Phibbs and Charlie Dewhirst.

Mr Dewhirst tweeted: "Are these views shared by your boss? I'm not sure it will be a vote winner in Hammersmith at the next election."

Having responded by writing, 'Oh I insulted the Queen, how very dare I'? Mr Zarb-Cousin issued an apology, saying: "To clarify earlier comments about the Queen: it was a joke & wasn't meant to be taken literally. I didn't mean to cause offence & apologise."

Mr Slaughter, a republican, said in a statement: "The Queen has given great service to our country and these comments are totally unacceptable. I've spoken to the member of staff in the strongest terms and he has apologised for his comments."

Mr Zarb-Cousin is a researcher for Mr Slaughter and also secretary for the Young Fabians, a socialist group for people under 30.