The former Conservative leader said the real “fear” of Eurosceptics should be a fresh referendum to halt Brexit – downplaying the claim that the UK could crash out with no agreement at all.
Mr Hague, speaking as the cabinet prepared to meet to back or veto the outline deal, urged Tory MPs to consider the shock resignation of Jo Johnson to campaign for a further referendum.
He told them: “What you have to really worry about here is that if you don’t take this opportunity to leave the EU – to get Brexit over the line – you might never leave at all.
“Many people share this point of view that the better alternative is to have a second referendum
“That means, of course, deferring leaving until next year and it would probably mean a different government.
“It would mean taking the next year having another referendum that might not resolve matters – that Brexit might not happen at all.”
Mr Hague defended the text struck between London and Brussels, arguing the UK was about to regain control of immigration policy and end “big” payments to the EU.
“It’s true there are many compromises, but did anyone think we’d be able to leave the EU without them?” he argued.
But he admitted the DUP’s refusal to back the deal was “very concerning” for the prime minister, adding: “The cabinet will need to take that into account.”
Mr Hague also dismissed an overnight leak from Brussels, which revealed the EU views the draft agreement as a way to “retain all the controls” over UK regulations permanently.
MPs should ignore a “leak overnight from somebody you have never heard of before”, he said – even though the author was EU negotiator Michel Barnier’s deputy.