Highgate councillor Sian Berry said she is “very proud” of the Green Party campaign after her third place finish in the mayoral race which saw her elected as a member of the London Assembly.

Ms Berry pledged that she will hold new Mayor Sadiq Khan to account and be a strong voice for the interests of Londoners, particularly on pollution, transport and the delivery of affordable housing.

She told the Ham&High: “I’m really, really pleased with the result. I think the number of second place choices (we received) is a huge vote of confidence. We came third quite decisively in the end, in the GLA as well as in the mayoral race.”

Ms Berry said she was pleased the Greens had kept out of the personal mud-slinging that marred the later stages of the campaign and had tried to focus on policy.

She said: “We ran a very positive campaign and put forward lots of ideas to solve everyday problems for Londoners.

“We didn’t let ourselves get dragged into the personality politics, although I did spend some time condemning the Conservative campaign towards the end because it was so divisive, and I felt it was my duty to say something about that.

“I feel quite proud of Londoners for rejecting the negativity and the parties who were trying to create fear and instead went for positivity and hope.”

She will carry on as a Highgate councillor for Camden. “The two jobs are perfectly compatible as the council meetings are all in the evening, whereas all of the GLA committee meetings are in the day.”

Ms Berry is currently in discussions about which committees she will sit on at the GLA, and is hoping her knowledge of transport and environmental issues will be utilised in her new role.

She said: “It is an exciting time now that we have myself and Caroline (Russell) on the GLA. I’m working on my first questions to the new Mayor which have to go in on Monday.”

The new Mayor has already made a couple of decisions which have concerned Ms Berry, including the withdrawal of an objection to expand City Airport.

She said: “That was one of the things that we all stood against, and it was one of our red lines when we were advising supporters on second preferences, so we are worried that he is going against this immediately.”

Another concern is the rumoured appointment of Lord Adonis by Mr Khan as an infrastructure tsar.

She said: “He’s got some very controversial views on housing estates...he basically wants to knock them down and start again, which I think is not the right approach at all, so I will be keeping a very close eye on that.”

Ms Berry said she is “hopeful” that Mr Khan will be able to deliver on his housing policies.

She said: “It was always going to be difficult for whoever won to solve the housing problems we have, but I will be working to make sure he sticks by the promises he made.”

Ms Berry is in favour of the Cycle-Superhighway 11 scheme, but said rather than having a cycling tsar - currently Andrew Gilligan, who was hired by Boris Johnson - she would like to see the appointment of a “healthy street” tsar who would work to make the streets safer in every respect.

She said: “Air pollution is the other big issue that the Greens will focus on at City Hall. We will carry on working with local campaigners throughout London, as we have done in Camden.”