A new poll suggests the long-standing St Albans MP Anne Main could lose her seat at the next General Election.

People's Vote campaign say figures taken from an online YouGov survey show that Mrs Main's seat may be at risk.

With Mrs Main gaining a majority of just over 6,000 votes in May 2017, the People's Vote says statistics suggest the Liberal Democrats might now overtake Mrs Main with a majority of 5.3 per cent next time around.

This was calculated by asking people's voting intentions for a General Election tomorrow compared to the 2017 election - the campaign say there was a 14.1 per cent Conservative slump and an eight per cent national swing towards the Liberal Democrats.

It says the swing increases further if new Prime Minister Boris Johnson campaigns for a No Deal Brexit.

The numbers were derived from more than 185,000 people surveyed between August 1 to 8, covering constituencies with the smallest Conservative majorities and where the Liberal Democrats came second in 2017.

Despite St Albans district voting more than 60 per cent Remain in the 2016 referendum, Mrs Main won in the constituency with a pro-Brexit manifesto in 2017.

The Liberal Democrats have launched a high profile Pro-EU campaign in St Albans.

Former president of YouGov, Peter Kellner, described Mr Johnson's tactic of taking a hard line on Brexit as "far from a deal sealer in any early election".

He said: "Given the volatility of recent general election campaigns, it's hard to see Boris Johnson opting for an early election as anything other than a mad gamble.

"Of course, he's always shown himself willing to take risks, but a lot of Conservative MPs could face a very premature end of their political career even if nothing changes from this poll."

Other Conservative constituencies which a People's Vote say would lose out include Richmond Park, St Ives, Cheltenham, North Devon, Cheadle, Lewes, Hazel Grove, Wells, and North Cornwall.

Mrs Main has been MP for St Albans since 2005. She did not respond to requests for comment.