Islington’s transport chief Claudia Webbe has announced her bid to be the Labour candidate in the Lewisham East by-election.

The seat has been vacated by Heidi Alexander, who has left to become Sadiq Khan’s deputy mayor for transport.

Rumours of Cllr Webbe standing emerged on Wednesday, and she is listed as third favourite at 5/1 on Ladbrokes, behind Phyll Opoku-Gyimah and Kevin Bonavia.

And this afternoon Cllr Webbe, who served as advisor to Ken Livingstone during his time as mayor and sits on Labour’s National Executive Committee (NEC), confirmed the news.

The staunch Jeremy Corbyn supporter, a distant cousin of ex-Blue musician Simon Webbe, wrote on her Twitter account: “I am standing to be the next Labour candidate for Lewisham East.

“I have recused myself from the NEC process. I have not been involved. Lewisham East is a vibrant and diverse constituency and I would be proud to be its next Labour MP.”

Cllr Webbe’s announcement comes less than a week after she was voted back in for a third term by 1,704 of her Bunhill constituents at the local elections.

It is not known whether Cllr Webbe would step down from her Islington cabinet position should she be elected on June 14. No changes to the Islington executive have been announced since Labour’s landslide council win last week, meaning Cllr Webbe retains the environment and transport portfolio she has held since 2014. If Richard Watts plans to make any changes, they would likely be announced at the annual council meeting on May 24.

Before becoming a councillor Cllr Webbe helped found Operation Trident in 1998 to tackle gun and violent crime in London’s black communities.

She also helped found and worked alongside anti-racist organisations and campaigns including the Anti-Racist Alliance and the National Assembly Against Racism.

In a lengthy statement announcing her decision, she added: “Over the past few months, Britain has changed. You can feel the change in the air as an outdated, unfair political model has been discredited. Jeremy Corbyn’s Labour Party is setting the agenda while the Tories flounder, holding office but no power.

“This version of Labour, with an honest and straightforward left-wing leadership, is now the biggest political party in Europe, with the May 2017 General Election proving beyond doubt that Britain is sick of business-as-usual, and the electorate wanting an alternative direction for our country.

“Jeremy has inspired a movement for change, I have been part of that from day one and having known and campaigned with him from way back and much longer, I am proud to call him a friend.”

Islington Council has a history of producing MPs-in-waiting.

Former leaders Margaret Hodge and Catherine West went on to win Parliamentary seats in 1994 and 2015 respectively – in Ms West’s case, less than a year after leaving the council.

Islington South MP Emily Thornberry, who was elected in 2005, had stood unsuccessfully for a town hall seat three years earlier.