In her maiden speech in the House of Commons yesterday, Ms Mortimer made reference to the story involving Lord Mandelson, who was Hartlepool MP between 1992 and 2004.

She said: “Although Mr Mandelson and I agree on very few things - and I, as a proud Northern lass, know the difference between mushy peas and guacamole - he was committed to injecting new life into Hartlepool as demonstrated by the redevelopment of Victoria Harbour. I am proud to pick up the baton of regeneration for my constituency.”

Lord Mandleson has previously said that the infamous rumour he once mistook chip shop mushy peas for avocado dip guacamole was a “great story but not true”.He said the mix-up was actually made by an American student helping out in a 1986 by-election but became wrongly linked to him over the years after a joke present from former Labour leader Neil Kinnock.

Jill Mortimer gave her maiden speech in Parliament on Tuesday

“I worked for the Labour party from 1985 to 1991 as the campaign director and at my leaving do he solemnly presented me with a large piece of fish and chips and mushy peas wrapped in the Daily Mirror, and said 'Enjoy the guacamole',” Lord Mandelson said in 2010.

“And from that moment on the story was transferred to me.”

Six things you might not know about Jill Mortimer

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'Proud Northern lass' Jill Mortimer aims guacamole jibe at Peter Mandelson in maiden speech