They are set to battle it out for one of the country’s most hotly contested constituencies at the next general election.

But this week, arch rivals Tulip Siddiq and Simon Marcus set their political differences aside as they joined forces in the name of a common cause – the fight to protect Hampstead’s famous crepe stall.

The two councillors were invited by the Ham&High to unite in support of La Crêperie de Hampstead and both willingly obliged.

Though they will soon by vying for Glenda Jackson’s Hampstead and Kilburn seat, they were all smiles on Monday as they joined up with crepe stand owner Edward de Mesquita and supporters, including Hampstead actor Tom Conti, outside the stall in Hampstead High Street.

Labour candidate Cllr Siddiq, who plans to leave her role as Camden Council’s cabinet member for culture in May to focus on her political fight with Conservative rival Cllr Marcus, said: “When it comes to local issues, it does not matter what your political persuasion is. We should unite together for the common good of people and to save local facilities.”

She added: “I have been coming here since I was 15, I went to school around the corner and it was always a treat to come here.

“It would be a great loss if it goes. It doesn’t just serve delicious food, it’s more like a little community hub or beacon, a jewel on the high street.”

In 2010, Hampstead and Kilburn was the second closest-run seat in the country, with Conservative Chris Philp losing by just 42 votes to Ms Jackson, who is standing down.

Cllr Marcus is now the Tories’ top hope for electoral gains in 2015, with the seat identified as the party’s number one target.

He said: “I’m delighted that the community has come together to support this cause and we will carry on working hard to get the best solution.

“I’m always pleased to work with other parties to get the best for the community.

“This is the way politics should be – politicians can work together and that’s what people want.”

The creperie is facing an uncertain future following a dispute with the King William IV pub next door.

Despite paying £40,000 per year to the pub’s freeholder, Heineken-owned Star Pubs & Bars, the creperie has been banned from using space in the pub to store stock and wash equipment.

There are also differences with leaseholder Elaine Loughran over the water and electricity supplies that come through the pub.

Mr de Mesquita says the conditions are so difficult that he has cut his opening hours and is now trading from Thursday to Sunday only.

Speaking about the support offered by the politicians, he said: “It’s nice to know there’s community support, it’s helping me and helping my staff.”

He added that he is in talks about moving to another spot in Hampstead, saying he will “leave no stone unturned to find a way to move forward”.