Zurich — Brexit will cut the value of the UK economy by £100bn a year by 2030 compared with staying in the EU, according to research commissioned by the People’s Vote, a group campaigning against leaving the bloc.

The study, by think-tank Niesr, comes as Prime Minister Theresa May begins selling her Brexit agreement to UK politicians. The deal was signed off on Sunday by EU leaders, who said it could not be renegotiated.

The Bank of England (BOE) will present its own analysis to lawmakers on Thursday, along with a scenario covering leaving without a deal. Parliament’s Treasury Committee will also hear testimony from economists, Treasury officials and BOE governor Mark Carney.

The People’s Vote study says that the current plan would mean a “catastrophic reduction in trade and investment.”

By 2030, GDP would be 3.9% below the baseline case of staying in the EU, total trade between the UK and the EU would fall by 46% and foreign direct investment would decline by 21%. Tax revenue would also suffer, according to the report.