Professor John Curtice said there were 50 Labour seats that were vulnerable to the Tories. Winning these could make the gains needed for the Tories to win an overall majority. However he admitted these seats were mostly in areas that are considered traditionally difficult for the Tories to win over.
As many as half are in the north of England, including Workington and Bishop Auckland which have never voted Conservative in a general election.
Workington is one of the towns expected to play a key role in determining Tory success or failure, according to analysts.
The good news for the Tories is that most of these seats voted to leave the EU in 2016.
In Workington – once a a Labour stronghold for generations – 66 percent voted Leave after the West Cumbrian town has been hit by unemployment and deprivation in recent decades.
Others such as Blackpool South and Great Grimsby voted overwhelmingly for Brexit.
The average Leave vote in all 50 Labour-held marginals was at 55 percent, notably higher than the nationwide figure of 52 percent.
Writing in the Sunday Telegraph, Mr Curtice said there were already clear indications of increasing Tory support in these traditionally Labour seats.
In the 27 Labour marginals where 55 percent or more people voted Leave, the Conservative vote had seen an increase of 10 points between 2015 and 2017.
Some, such as Ashfield, Penistone and Stocksbridge, and Rother Valley had become recently become marginal seats because of a strong Tory swing.
According to Mr Curtice, it was “inevitable” that the Tories would lose some seats to the Liberal Democrats.
A dozen seats are at risk, with the Tory lead less than 20 points in the last general election, and they were almost all previously held by the Lib Dems until 2015.
Of these, Brecon had already been won by Jo Swinson’s party in a by-election in August.
Mr Curtice predicted that Tory marginals such as North Cornwall and North Devon would be unlikely to flip, having voted to leave the EU.
In Scotland, Tory support has fallen and with the majority of Scottish voters backing Remain, it would be difficult for the Tories to keep their current seats.
His comments will come as a relief to Mr Johnson, who is only eight points ahead of Jeremy Corbyn in a new poll.
A survey from ORB International revealed the Tories are on 36 percent and Labour just behind at 28 percent, sparking concerns over the future of Brexit.
It showed the Liberal Democrats at 14 percent, with Nigel Farage’s Brexit Party at 12 percent.
Johnny Heald, from ORB International, said: “Boris Johnson has a lead over Jeremy Corbyn but he will need to increase this over the next six week if he wants a comfortable majority in the Commons.”
“Look out also for those who voted remain in 2016.
“At the moment they are 2:1 voting Labour over the Lib Dems.”
He added: “Jo Swinson will need to attract these voters if the party is to mirror gains made in the Euro elections.”
The Prime Minister has warned that a vote for the Brexit Party risks Mr Corbyn moving into Number 10.
Mr Farage has pledged to field candidates for the Brexit Party across England, Scotland and Waled if no agreement is formed by November 14.
