British opposition leader Jeremy Corbyn said on Wednesday Labour would vote against a Brexit deal based on Theresa May's proposals, the strongest warning yet to a prime minister whose plan to leave the European Union is hanging by a thread.
On the final day of his party's annual conference, Corbyn sought to show that his party was ready to take over the reins of power, setting out in the most detail yet what he called "a radical plan to rebuild and transform our country" and promising new jobs from a green "revolution".
Corbyn also made a direct bid for the support of those outside the British capital who voted to exit the EU, often in frustration at feeling left behind by a London-based elite, saying Labour was ready to take over the tortured Brexit talks.
Britain is not due another election until 2022, but Labour is already preparing for a snap vote.
Despite her denials, few are ruling out an early election after May's already precarious position was further weakened last week when the EU rebuffed her Brexit proposal, known as "Chequers", which is also unpopular in her Conservative Party.
Corbyn, a veteran eurosceptic who in 1975 voted "No" to Britain's membership of the then-European Community, said Labour respected the outcome of a 2016 referendum when Britons voted to leave the EU, the biggest shift in foreign and trade policy in more than 40 years.
"As it stands, Labour will vote against the Chequers plan or whatever is left of it and oppose leaving the EU with no deal," Corbyn told a packed hall at the conference in the northern English city of Liverpool.
"And it is inconceivable that we should crash out of Europe with no deal — that would be a national disaster. That is why if parliament votes down a Tory deal or the government fails to reach any deal at all we would press for a general election. Failing that, all options are on the table."
Corbyn hoped to steer his annual party meeting away from Brexit, which has divided his party just as it has done May's Conservatives and much of the country. Britain is due to leave the EU on March 29, 2019.
The Labour leader, seeking to paper over his party's divisions, has backed a call to keep open the option of holding a second referendum on staying in the EU despite opposition from some powerful trade unions.