Pro-EU campaigner Gina Miller has criticised the Prime Minister’s no-show at Wednesday’s leaders’ debate as “totally scandalous”, implying it does not bode well for her negotiations in Europe over Brexit.

The businesswoman, who was behind a successful legal challenge over Article 50, is leading a Best For Britain campaign, urging young people to vote tactically to stop an “extreme Tory Brexit”.

Ms Miller stood alongside pro-EU Liberal Democrat candidate for Vauxhall George Turner on a boat at a south London dock, in a bid to mirror a picture taken last year featuring former Ukip leader Nigel Farage and the then Vauxhall MP, Labour’s Kate Hoey, who campaigned to leave the EU.

Asked about Theresa May’s absence at the BBC debate, she told the Press Association: “I thought it was totally scandalous.

“She’s the one who called the election, she should be engaging in debate and going out on the doorstep, talking to ordinary people. (She should) not be doing invitation-only events around the country and refusing to turn up and debate other leaders.

“What does that say about her negotiating with 20 other leaders, if she can’t even negotiate with domestic leaders?”

The Best for Britain campaign, launched in April, aims to combat “apathy” amongst an electorate suffering from voter fatigue, Ms Miller said.

She backed Mr Turner’s candidacy, and said the group will be pushing for “real game-changers, strong candidates who will hold whatever government to account and will fight this extreme Brexit that the Tories are peddling”.

Around 78% of Vauxhall residents voted to remain, a stance at odds with Ms Hoey, who staunchly campaigned to leave the EU, alongside Mr Farage.

Before the pair joked about the similarities between their pose and a famous scene from the film Titanic between Jack and Rose on the bow of the ship, Mr Turner echoed Ms Miller’s remarks about Mrs May and said: “She’s a complete law unto herself.”

Ukip leader Nigel Farage and Kate Hoey on board a boat during the Brexit campagin (Stefan Rousseau/PA)
Ukip leader Nigel Farage and Kate Hoey on board a boat during the Brexit campagin (Stefan Rousseau/PA)

Pro-Remain and anti-EU demonstrators took their battle to the waters in the run-up to the referendum last year in a shouty Thames showdown which saw Mr Farage and Ms Hoey take on philanthropist Bob Geldof in a protest about EU fishing policies.

Mr Turner, who is attempting to win the south London seat from Ms Hoey, who has represented the constituency since 1989, said: “There (is) no illusion as to what the people of Lambeth feel about Brexit. It was the highest voting Remain constituency in the country.

“We can’t be in a situation where their MP so brazenly refuses to listen to the constituency. That is what has happened here.”

The Vauxhall Liberal Democrats recently released a campaign leaflet which merged the faces of Ms Hoey and Mr Farage, beside the words “Hoey out! Vauxhall deserves better”.