Pro-Brexit campaign groups refuse to disband because they’re worried Boris Johnson will betray them Leave campaigners want to channel the energy of grassroots supporters

After the 2016 referendum, many of those involved in the Leave campaign stepped away from politics – and then watched in horror as Theresa May negotiated a Brexit deal they thought sold out voters, while Remainers launched a barrage of efforts to secure a second referendum.

They are determined not to make the same mistake now that Brexit is actually happening. Leading campaigners say they will remain involved in the debate, seeking to ensure Boris Johnson keeps his promise to dump EU regulations and mobilising a base of thousands of Leave supporters to act on issues they care about.

Wealthy Eurosceptics are still donating money to the cause, according to senior activists. A number of influential Leavers are understood to have joined a new group called “Phoenix”, which will meet in London every month and discuss how to channel the energy seen in the pro-Brexit cause over recent years.

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Andy Wigmore, the right-hand man of Brexiteer tycoon Arron Banks in the campaign organisation Leave.EU, told i his group would continue operating. “We kept this thing going after the referendum just as a little pressure group, but it’s kept growing,” he said. “It would be daft to close down.”

‘We don’t trust them’

Leave.EU has a social media network of more than a million people and regularly mobilises them on causes far removed from Brexit. Mr Wigmore highlights HS2 rail and crime as issues that its followers – who cross party lines – have strong views about. Last week, the group raised more than £60,000 for the failed attempt to ensure Big Ben could ring on 31 January.

While Nigel Farage’s Brexit Party is highly unlikely to continue in its current form, senior members of the party – who deeply mistrust the Prime Minister – intend to keep up their campaigns. Brexit Party MEP Claire Fox, a former Marxist, is hosting a conference in the North of England to discuss the way forward.

Gawain Towler, former head of communications for Ukip and the Brexit Party, said it was an error to dial back operations in 2016 because “we assumed it would all be OK”. He told i: “There’s a feeling that we don’t trust them. It’s a question of banking what we’ve got and moving on. There are definitely groups of people discussing and meeting up.”

He added that the moment Britain formally leaves the EU next week “will be interesting – but it’s just for show, it’s not real”. The important battles will come as Mr Johnson negotiates with Brussels and comes under mounting pressure to agree to a compromise which minimises the disruption faced by big businesses, Mr Towler said.

Leavers are considering creating a network of organisations similar to some right-wing thinktanks, which are headquartered in Westminster and try to influence MPs and the media, but also have operations across the UK targeting ordinary voters by highlighting local issues. They also want to encourage activists who have been sucked into politics by the Brexit debate to run for office in their own right.

Efforts to maintain the grassroots groups which have helped sustain Eurosceptic energy could prove tricky if resources dry up. One prominent campaigner warned that such groups are vulnerable to infiltration by the hard right if there are not enough moderate activists putting in time to monitor their activities and expel malicious actors.