Brexit: MPs condemn 'unrealistic' government analysis

Treasury select committee also criticises failure to look at economic impact of backstop

The government kept MPs in the dark when it presented an overly optimistic assessment of its Brexit deal, rather than a realistic prediction of the final relationship, an influential committee of MPs has found.

The Treasury select committee, chaired by the former cabinet minister Nicky Morgan, found that the UK government had also failed to give adequate information on how the backstop mechanism would affect the economy.

A backstop is required to ensure there is no hard border in Ireland if a comprehensive free trade deal cannot be signed before the end of 2020. Theresa May has proposed to the EU that the whole of the UK would remain in the customs union after Brexit, but Brussels has said it needs more time to evaluate the proposal.

Related: Brexit chaos: what happens next?

This soft Brexit compromise has been championed by the former Conservative minister Nick Boles as a plan B for leaving the European Union if Theresa May's withdrawal agreement is defeated in the Commons.