Siân Berry has triggered a by-election in Highgate after standing down as councillor.

The only Green Party member in Camden Council's chamber, Cllr Berry will stand down on Friday (October 20) after nine years serving the ward.

The 49-year-old wrote to her constituents telling them she felt "sad" resigning but wanted "to focus on my work to be the next Green MP for Brighton Pavilion".

She will continue her role on the London Assembly and run for re-election for her seat in May while actively running for the Brighton seat at the next general election, that could be held as late as January 2025.

Cllr Berry held on to the Highgate seat left by Green councillor Maya de Souza in 2014.

In her letter she said her time on the ward had been "rewarding and enjoyable".

Among the work she most enjoyed she said: "Standing up for estate residents - chasing up so many repairs, holding contractors to account alongside residents, and challenging council policies for fairer access to council housing."

She campaigned for combatting air pollution and traffic from a citizen science project in 2013 and worked with resident groups to win priority funding for improvements in Highgate.

She also, together with Highgate's Labour representative Cllr Anna Wright, brought the Mortimer Terrace Nature Reserve into community hands, serving as a trustee, "as well as working all my shifts in Highgate Library as a volunteer from the very start".

"Highgate does politics differently, and I know residents value its unique Green voice," she added.

From 2018 to 2021 Ms Berry was co-leader of the Green Party of England and Wales alongside Jonathan Bartley, and as its sole leader from July to October 2021.

She stood down over the party’s “mixed messages” on transgender rights.

Ms Berry has defended her decision to bid to replace Brighton Pavilion's MP Caroline Lucas, who is retiring.

She told the Brighton Argus:  “No one knows when the general election will be. It may be very soon and come before the London elections or it could be as much as eight months afterwards or even more.

“Whatever happens about the timing of the election, I am making a home in Brighton and will continue to meet and listen to residents all across the constituency while working hard as an elected representative on behalf of millions of citizens, demonstrating my ability to hold to account the current mayor, the next mayor and the next government."