A mobilised Leave vote could be a “real problem” for Chester’s wafer thin Labour majority, according to a political academic.

Dr Stuart Wilks-Heeg, head of politics at the University of Liverpool, said should Theresa May be able to stir up strong feelings in city voters who pushed for the UK to leave the European Union last year, it could “tip the balance” in the snap General Election and hand the seat back to the Conservatives.

Dr Wilks-Heeg also said in constituencies where there was a clear Leave vote in local authority areas, such as Alyn and Deeside, Delyn and Wrexham, former Labour electors could swing back to Ukip or the Tories.

Members of Parliament overwhelmingly supported Mrs May’s call for a General Election when they voted by 522-13 in favour of a national vote to be held on June 8.

Labour MPs David Hanson and Mark Tami will defend their seats in Delyn and Alyn and Deeside while Ian Lucas confirmed he would stand in Wrexham.

Susan Elan Jones is to ask for voters’ help to remain as the MP for Clwyd South while Justin Madders will hope to extend his stay as the representative of Ellesmere Port and Neston.

Ms Elan Jones and Mr Hanson did not take part in yesterday’s vote. Chester MP Chris Matheson abstained.

Dr Wilks-Heeg told the Leader Mr Matheson’s Labour majority of 93 in Chester could go to either the Conservatives or the Liberal Democrats with the EU referendum in play as the main issue.

He said: “It is so difficult to predict with any certainty.

“Brexit is going to be the issue but in a sense it has already been settled as we know we are leaving (the European Union).

“It’s a major headache for the Labour Party and different things will happen in different constituencies.

“Where you have marginals, like Chester, that could tip the balance.

“The real problem for Chris Matheson is if Theresa May can mobilise the Leave vote.”

In the EU referendum Cheshire West and Chester voted narrowly to Leave but it is calculated that voters living in the city of Chester opted equally narrowly to Remain.

Dr Wilks-Heeg said it was for this reason that a surprise victor in the seat could be Tim Farron’s Lib Dems.

Looking across the border to North East Wales constituences, Dr Wilks-Heeg said problems remained for Labour, despite Alyn and Deeside, Delyn and Wrexham being traditional strongholds for Jeremy Corbyn’s party.

He said: “In constituencies where there is a clear leave vote and a functioning high Ukip sympathy, we could see a switch to the Conservatives.

“The Ukip vote could hold up against Labour and there could be a possible increase for Plaid. It feels like a giant by-election, where all the rules are off.”

The political analyst added that unlike in 2015, when Ed Miliband’s Labour looked to be pushing David Cameron’s Conservatives all the way – only for the opinion polls to be hopelessly wrong – the result on June 8 might be more obvious.

“The polls usually overestimate the Labour vote and underestimate the Tory vote,” he said.

“They don’t suggest it’s going to be close this time and I wouldn’t expect that to change in a short space of time.”