British Member of Parliament, Jo Johnson, leaves the BBC's Broadcasting House, in London, Britain November 10, 2018. REUTERS/Henry Nicholls

LONDON (Reuters) - Former minister Jo Johnson said that the future of Britain’s ruling Conservative Party would be in peril if Prime Minister Theresa May proceeded with Brexit, hours after Britain agreed the draft text for leaving the European Union.

The former junior transport minister, who is the younger brother of former Foreign Secretary Boris Johnson, issued a searing critique of May’s Brexit deal last week when he unexpectedly quit and called for a second referendum.

“The future of the Conservative Party will be gravely imperiled if we are held responsible for taking the country into this absurd new relationship with the EU where vast swathes of our economy will be governed by rules that we have no hand at all in shaping, ” Jo Johnson told a political rally in London.

The event was held near parliament hours after Britain hammered out a draft divorce deal, thrusting May into one of the most dangerous moments of her premiership as she challenges her divided cabinet to back the deal.

Johnson said a number of ministers would be “looking deep into their consciousness” to see if they can support the deal.

He said the public had been “duped” by the promises made during the referendum by Brexit campaigners and the vast gulf between what they were promised and reality meant voters must be give another chance to confirm they want to leave the EU.