The UK is facing a post-EU referendum "right-wing coup" as Britain starts divorce negotiations with the EU, Green Party leaders will claim on Friday (31 March). Caroline Lucas MP and Jonathan Bartley will issue the warning at the party's spring conference in Liverpool in the North West of England.

"[Donald] Trump and [Nigel] Farage are right about one thing. Globalisation has let people down. [But] repairing the damage caused by globalisation needs people to genuinely get control of their lives back," Lucas will say.

"It needs investment in new jobs in a new and hopeful future – one that thinks locally, as well as globally. It will be done through unity not through division. And it will not be done by scapegoating and shaming that turns neighbours against one another and singles out people of colour."

Bartley, meanwhile, will attack the Conservative government and the Labour Party over their handling of the Article 50 process, just days after the UK's diplomat to the EU, Sir Tim Barrow, handed the notification letter to EU Council president Donald Tusk.

"When this Government claims to speak on behalf of the British people, what they really mean is this. We have a blank cheque. We can do all the things we wanted to do – cut the NHS, scrap environmental laws and give tax breaks to big business – and do it in the name of Brexit," he will say.

"And where, in all this, are the Official Opposition? The Labour Party has failed in its essential duty to hold the government to account. They didn't even put up a fight. Instead they waved a white flag, and pledged unconditional support for Article 50 – they would vote for it come what may."

The conference comes more than a month before the local and metro-mayoral elections in May. The latest national opinion poll from YouGov for The Times, of more than 1,900 people between 26 and 27 March, put the Greens on 3% – just below the party's 3.8% at the 2015 general election.