Britain's Attorney General Geoffrey Cox is seen outside Downing Street in London, Britain, March 12, 2019. REUTERS/Simon Dawson

LONDON (Reuters) - Attorney General Geoffrey Cox said on Tuesday a revised divorce deal with the European Union had not given Britain legal means of exiting the so-called backstop arrangement unilaterally if “intractable differences” arose.

Cox’s advice is crucial to winning over eurosceptic members of parliament in Prime Minister Theresa May’s Conservative Party, and she had hoped that revisions to a Brexit deal over the Irish backstop, or protocol, secured late on Monday would offer enough assurances to get her deal through parliament.

“However, the legal risk remains unchanged that if through no such demonstrable failure of either party, but simply because of intractable differences, that situation does arise, the United Kingdom would have ... no internationally lawful means of exiting the Protocol’s arrangements, save by agreement.”