The Green Party will stand in Hampstead and Kilburn unless Labour agrees to pull out candidates in Brighton and the Isle of Wight by noon tomorrow.

Ham & High: If the Greens had stood down, they would have helped Ms Siddiq in her battle to defeat Tory Claire-Louise LeylandIf the Greens had stood down, they would have helped Ms Siddiq in her battle to defeat Tory Claire-Louise Leyland (Image: Archant)

Members rejected a potential alliance with the Labour Party as a “one-way street” – but left open the possibility of pulling their candidate if Labour meets the deadline.

If there is no change, John Mansook will represent the Greens in the marginal constituency won by Tulip Siddiq in 2015 by 1,138 votes – with the Tories close behind in second place.

The Greens then managed 2,387 votes, meaning if those same voters backed Labour next month as part of a “progressive alliance”, they could theoretically block the Conservatives’ route to victory.

But at a meeting last night, Green members instead backed their candidate John Mansook to stand because of a “lack of movement” by Labour on forming similar alliances in the Isle of Wight and Brighton.

Ham & High: John Mansook. Picture: Green PartyJohn Mansook. Picture: Green Party (Image: Archant)

Green members – including Mr Mansook – were keen to thank Ms Siddiq for her willingness to attend the meeting and for pushing Labour’s National Executive Committee to stand aside in the two seats, as well as for her voting record on “key Green issues” like fracking, Trident and HS2.

Mr Mansook said: “Any electoral alliance needs to be a true alliance, not a one-way street. Sadly there hasn’t been any movement towards this from the Labour Party nationally.

He added: “One of the Green Party’s key platforms in the upcoming campaign will be to change our unfair voting system, so that discussions like this are unnecessary and people can vote for what they believe in.”

The Greens added a condition to their decision stating that Mr Mansook would step down if Labour change their mind on national alliances by noon tomorrow.

Ms Siddiq said she was pleased to be given the “important opportunity” to speak to “dozens of progressive and politically engaged residents, particularly to discuss my pro-European stance and my record of supporting our local environment”.

She added: “Attendees were clear in their dismay over the Conservatives’ rush towards a hard Brexit, their impending cuts to local schools, and their insistence on disastrous projects such as HS2.

“I am proud to have worked tirelessly as MP for Hampstead and Kilburn over the past two years, and I look forward to discussing my record with thousands of residents in the weeks ahead.”

Meanwhile John Holmes, co-chairman of Camden Greens, said Mr Mansook is an “excellent local candidate” who is “deeply connected” with Hampstead and Kilburn issues.

He added: “Voters deserve the option of being able to vote for him and for the Green Party’s unique policies, including a commitment to reverse privatisation in the NHS and measures that will dramatically cut Britain’s contribution to climate change.

“We can only deprive voters of that opportunity if Labour works with us to increase our Green voice in Parliament.”