Forbes won 10,484 votes, beating the Brexit party’s Mike Greene, who took 9,801 votes, a margin of just 683. The Conservatives were beaten into third place with 7,243 votes. Turnout was 48%.
Nigel Farage, the Brexit party leader, left the count through a backdoor just minutes before the result was announced.
In a result that will alarm Tory headquarters Lisa Forbes took the seat despite winning less that a third of the vote – showing how Jeremy Corbyn could sneak a general election victory.
The narrow result saw the Brexiteer vote split between the Brexit Party and the Tories – combined they would have been enough to easily win the seat in an area what voted Leave in 2016.
The upstart eurosceptic party candidate Mike Greene lost the marginal by less than 700 votes to Corbynite Ms Forbes.
After a long night of counting, and an even longer campaign, the Labour party have been declared the winners of the Peterborough by-election. Lisa Forbes, the Labour party candidate, will replace Fiona Onasanya who was ousted from the seat earlier this year after she was convicted of perverting the course of justice. Forbes won 10,483 votes in the election, ahead of the Brexit party on 9,801, and the Conservatives on 7,243.
The polls have closed in the Peterborough parliamentary by-election, with the result due in the early hours of Friday morning.
Keep up-to-date with everything that is happening through the Peterborough Telegraph live blog below.
The polls in the Cambridgeshire city opened at 07:00 BST and will close at 22:00.
Results are expected in the early hours of Friday and coverage can be watched on BBC One’s This Week from 23:35.
Vote triggered after former Labour MP Fiona Onasanya was jailed for lying about a speeding offence.
Estimating around 70% of his support is coming from Conservative voters angry at Theresa May’s failure to deliver Brexit, however, Greene says: “They are standing up and saying ‘I support Brexit’ and it’s a bit of an ‘I Am Spartacus’ moment. The fears that have been pushed on them by the media and institutions are dropping away and it’s like ‘I Am Spartacus, I vote Brexit’.”
A by-election in Peterborough offers the chance of Parliamentary representation