London Green Party members have thrown down the gauntlet to Zac Goldsmith and Sadiq Khan, as they lay out their four ‘red line’ policies either candidate must back before Greens officially give them their 2nd preference support for May 5th.

London Green Party members voted Monday night to mandate talks between Sian Berry and the two leading candidates from the Conservatives and Labour.

If one of them back Berry’s four policy asks, it’s likely that members will be encouraged to give their second preference to that candidate in just seven weeks’ time.

It follows news yesterday that the Greens’ Sian Berry is currently joint third with Lib Dem Caroline Pidgeon in the running for third place in the Mayoral race, meaning Green voters’ 2nd preferences could decide who is the next Mayor of London. No Mayor of London has ever won a majority vote on first preferences.

Berry will demand the two main candidates back an end to road building, airport expansion and enforced council estate demolitions, and to reduce London’s inequality.

For three of the four previous elections the Greens have voted to back Ken Livingstone for second preference – as an Independent in 2000 and as the Labour candidate in 2008 and 2012.

In 2004 Greens refused to back a candidate – meaning it is not unimaginable that this could happen again given many Greens’ concern over comments from Khan about the rich: “I welcome the fact that we have got 140-plus billionaires in London”, Khan recently said in an interview for the Spectator.

Depending on the progress of these discussions, it will take a further vote in April and decide which, if any, candidate, to endorse as second choice.

In a statement following its meeting last night, the Federation said:

“Greens in London want positive change and a Green Mayor is the best way to deliver that. But Londoners will be able to give two Mayoral candidates their support, and to elect more Greens to the London Assembly. The next Mayor could do a lot to tackle air pollution, climate change and housing, but he or she could also make the situation far worse.

“We are putting down four red lines, requiring Zac Goldsmith and Sadiq Khan to rule out any major road building, airport expansion or enforced council estate demolitions, as well as to make a clear commitment to reducing inequality. That could clear the way for the party to make a strong recommendation of support next month.”

Sian Berry said:

“The Greens have grown in strength and experience over 16 years and I think our policies stand alone. We’re the only party that will say no to big road building, airport expansion and forced estate demolition.

“I’m sure my supporters will have their own thoughts about who, if anyone, will get their second preference. But I will now be seeking answers from Sadiq Khan and Zac Goldsmith on theses questions to see if either of them merit the party’s formal endorsement.”

Bright Green will be following the debate closely…