Kate Hoey has pledged to fight moves to deselect her after her local Labour party overwhelmingly passed a vote of no confidence against the strongly pro-leave MP over her support for the government in key Brexit votes.

Hoey, who has represented the pro-remain south London constituency of Vauxhall since 1989, said she was “quite relaxed about the vote” and would not let it change the way she acted in parliament.

The motion, passed at a meeting of the Vauxhall Labour party on Thursday evening, calls for Hoey to lose the Labour whip and for the party’s national executive not to allow her to be reselected for the seat.

It carries no official force, but local members can seek a so-called trigger ballot that could deselect Hoey. Forty-two members voted against the MP with three abstentions. No one voted in her favour.

Hoey, who is in Zimbabwe as an election observer, has sometimes seemed a slightly anomalous fit for her inner-city constituency – she is a firm supporter of foxhunting – but is regarded as a diligent and independent-minded local MP. She has a majority of 20,250.

Disquiet in the local Labour party over Hoey’s pro-Brexit views – she campaigned alongside Nigel Farage during the EU referendum – culminated earlier this month when she defied Labour whips on key Brexit votes.

She put her name to an amendment to the customs bill, ruling out a customs border in the Irish Sea, which was put forward by the pro-Brexit European Research Group (ERG), headed by Jacob Rees-Mogg, and also backed by the DUP.

Hoey was also one of four Labour MPs to support the government in defeating an amendment calling for a post-Brexit customs union, a vote that if lost could, according to the warnings of Conservative whips, have triggered a general election.

The local party motion said Hoey was elected on a Labour manifesto that rejected Theresa May’s Brexit plans, and censured her for “repeatedly reneging on those commitments, and ignoring the clearly stated views of her constituents and the national and local Labour party”.

It accepted MPs could defy the whip and vote with their conscience, but said this “cannot extend to collaborating with the ERG and DUP” in the Commons, and “propping up a failing government” by supporting it on the customs union. It also criticised Hoey for her views on hunting, as well as issues such as grammar schools.

A statement from Hoey, read to the meeting, disputed that she had prevented the government from falling, saying she had simply opposed a “backhand way of staying in the customs union”.

The statement added: “Many of the issues raised are long in the past, and I have since then been subject to the vote of Vauxhall residents and re-elected each time.”

The MP told the Guardian in a statement that the motion was “not a surprise”.

She said: “My local party activists are solid EU remainers. I will always put my country before my party and helping my constituents is a priority. After 29 years as an MP I am quite relaxed about the vote and it won’t influence in any way how I vote in future.”

