A Labour councillor in Stevenage has defected to Reform UK.

Cllr Mason Humberstone, who represents Old Town ward and was first elected to the borough council in 2023, becomes the first Reform councillor on the authority.

His decision comes months after Reform UK won five of the six Stevenage seats on Hertfordshire County Council.

Explaining his move, Cllr Humberstone said: "I have not left the Labour party, Labour has left us.

"The party I joined is lost, without vision, and I no longer know who it is working for – too often it serves a metropolitan elite disconnected from the realities of the people it is meant to represent.

"When policies are pursued to the detriment of the British people, I cannot in good conscience remain aligned with a party that wilfully undermines our great democracy and country.

"Reform is the only party capable of delivering the change we need and of finally putting our nation and the British people first."

Cllr Humberstone was criticised by Cllr Richard Henry, leader of Labour-run Stevenage Borough Council, who told the Local Democracy Reporting Service he was "really disappointed" by the decision.

Cllr Henry accused Cllr Humberstone of "jumping ship with no fair warning for personal and political gain", and called for him to "seek a new mandate from Old Town residents in a by-election".

He continued: "I made every attempt, above and beyond what would be considered reasonable, to accommodate and mentor Cllr Humberstone as he brought many challenges to the table in terms of his attendance, punctuality, adherence to commitments, dedication to the role and much more."

In the last year, Cllr Humberstone has been at 10 of the 33 council and committee meetings he was expected to attend.

A local Labour party source said: "Mason showed a lot of promise and potential when he joined the party, but the reality is he fell extremely below the mark."

Kevin Bonavia, Stevenage's Labour MP, also backed calls for a by-election and said he was "deeply disappointed" that Cllr Humberstone had moved to a party "who thrive on fear and division and have no practical solutions for our country's future".

Mr Bonavia added: "I will not be distracted by political opportunism as I continue to focus on working day and night to secure positive changes for our town and villages as our local MP."

A Reform UK spokesperson said they were "delighted" that Cllr Humberstone has joined the party, and continued: "We welcome anyone who shares our vision for integrity, accountability and meaningful change to join us."