In 2017, Ms Whysall came within 353 votes of taking the seat, but she was again narrowly defeated with Ms Villiers winning by 1,212 votes.

Five candidates stood in the constituency and the full result, declared in the early hours Friday 13 December, shows the narrowness of the Conservative majority in what became a two-horse race:

Theresa Villiers (Conservative) 25,745
Emma Whysall (Labour) 24,533
Isabelle Parasram (Liberal Democrats) 5,932
Gabrielle Bailey (Green Party) 1,288
John Sheffield (Advance Together) 71

Ms Villiers was assisted by the Brexit Party’s decision to withdraw its candidates from Conservative held seats, which meant the Leave vote was not split which might have helped her Remain opponents.

But the combined vote for Labour, Liberal Democrat and Green candidates was an indication of the potential threat to Ms Villiers if there had been wider support for tactical voting.

When added together, Ms Whysall, Ms Parasram and Ms Bailey – who had all promised to back remain in a second referendum – secured a total of 31,753 votes, which would have been more than enough to have defeated Ms Villiers.

A surge in Liberal Democrat support was enough to secure Luciana Berger second place in Finchley and Golders Green where the Green Party stood aside as part of a Remain Alliance. As a result, Labour slipped to third place.

The full results in the two other constituencies in the Borough of Barnet were:

Finchley and Golders Green:

Mike Freer (Conservative) 24,162
Luciana Berger (Liberal Democrats) 17,600
Ross Houston (Labour) 13,347

Hendon:

Matthew Offord (Conservative) 26,878
David Pinto-Duschinsky (Labour) 22,648
Clareine Enderby (Liberal Democrats) 4,628
Portia Vincent-Kirby (Green Party) 921