Labour will only let Theresa May trigger Article 50 to start the process for Britain's exit from the European Union if she guarantees access to the single market, Jeremy Corbyn has said.
The opposition will join forces with Tory Remain supporters and other parties to block Article 50 if the Prime Minister does not agree to Labour's "Brexit bottom line", the party's leader told the Sunday Mirror.
Mr Corbyn suggested Ms May - who has a slim Commons majority - would be forced into an early election if she failed to meet Labour's demands, the newspaper reported.
The Government is appealing a High Court ruling ordering that the PM must seek MPs' approval to trigger Article 50.
Mr Corbyn told the Sunday Mirror: "The court has thrown a big spanner in the works by saying Parliament must be consulted. We accept the result of the referendum.
"We are not challenging the referendum. We are not calling for a second referendum. We're calling for market access for British industry to Europe."
Earlier on Saturday Mr Corbyn would not answer ITV News' question of whether he would be happy for an early election or not.
However, the Labour leader told the Sunday Mirror that his party was "ready" for an election.
"We have the members, the organisation and the enthusiasm. We welcome the challenge.
"It would give us the chance to put before the British people an alternative economic strategy for this country."
It comes after the PM was urged to calm the backlash sparked by the controversial High Court ruling on the process for leaving the European Union.
On Thursday the High Court ruled Ms May does not have the power to start the Brexit process by triggering Article 50 without a vote in Parliament.
Former attorney general Dominic Grieve described the attacks as "chilling and outrageous" and "smacking of the fascist state".
Justice Secretary Liz Truss bowed to pressure from barristers to speak out but only went as far as saying the independence of the judiciary is the "foundation upon which our rule of law is built".
Ms Truss added that the Government would be appealing the High Court's decision on Article 50.