UK Labour leader Jeremy Corbyn has said his party will do everything to prevent a no-deal Brexit, and said he is ready for a general election.
Mr Corbyn would not say exactly when he would call a vote of no confidence against Prime Minister Boris Johnson but said he would "look at the situation" when parliament returns in September.
"But it's also up to the prime minister and what he decides to do as well because if he is trying to take us out on a no-deal Brexit at the end of October we will oppose that."
When asked if he could guarantee that he would call a confidence motion before Britain leaves the EU he said Labour would do it at a time of its choosing.
He added: "I can guarantee you this, we will do everything to prevent a no-deal Brexit, we will do everything to challenge this government, and we will do it at a time of our choosing."
Mr Corbyn told Sky's Sophy Ridge On Sunday that he was not worried about going to the polls against new British Prime Minister Boris Johnson.
He said: "I've got my summer campaign plan in place, we've got most of our candidates selected in all our marginal constituencies."
When asked if he was worried about competing with Mr Johnson at the next election, Mr Corbyn said: "Not in the slightest. We'll go out there and we'll make our case.
"I don't get involved in personal abuse, I don't make any personal abuse, I don't do personal, as far as I'm concerned the issues are too serious."
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He added: "Parliament gets back in September and I think it's at that point we will look at the situation.
It comes as the Tories have been boosted by a "Boris bounce" after the election of their new leader, according to polls.
Since Boris Johnson became Prime Minister after being declared party chief by Conservative Party members, the party has gained 10 points to stand at 30%, a survey by Deltapoll for the Mail on Sunday showed.
That puts them five points ahead of Labour at 25%, with the Liberal Democrats on 18% and the Brexit Party on 14%.
But if Labour was to drop Jeremy Corbyn as leader, the poll says the party would shoot into the lead at 34%, with the Tories on 28%, the Brexit Party on 14% and the Lib Dems on 13%.
Chancellor Sajid Javid said there would be "significant extra funding" this week to get Britain "fully ready to leave" the EU on 31 October, with or without a deal.
The additional spending will include financing one of the country's "biggest ever public information campaigns" to ensure individuals and businesses are ready for a no-deal exit, Mr Javid told the Sunday Telegraph.
The Sunday Times said Mr Johnson had put together a Brexit "war cabinet" of six key ministers and that the Government was tasked with delivering EU withdrawal on 31 October "by any means necessary".
Mr Gove wrote in the newspaper: "With a new Prime Minister, a new Government, and a new clarity of mission, we will exit the EU on October 31. No ifs. No buts. No more delays. Brexit is happening."
The poll boost came after Mr Johnson set out an eye-catching domestic stall promising a £3.6bn boost for left-behind towns as he sought to shift the political spotlight from Brexit.
He also pledged funding for a major new rail link between Manchester and Leeds, and promised action on housing and crime, despite insisting he was not preparing for a snap autumn election.
Britain ramps up preparations for "very real prospect" of no-deal Brexit
The British government is working on the assumption that the European Union will not renegotiate its Brexit deal and is ramping up preparations to leave the bloc on October 31 without an agreement, senior ministers have said.
Mr Johnson, who took over as British prime minister on Wednesday with a promise to deliver Brexit by the end of October has said he plans to seek a new exit deal withthe EU.
The EU has said repeatedly that the deal cannot be reopened.
Leading Brexit supporter Michael Gove, who Mr Johnson has put in charge of no deal preparations, wrote in the Sunday Times newspaper that the government would undertake "intensive efforts" to secure a better deal from the EU.
"We still hope they will change their minds, but we must operate on the assumption that they will not ... No deal is now a very real prospect and we must make sure that we are ready," Mr Gove wrote.
"Planning for no deal is now this government's no. 1 priority," he said, adding "every penny needed" for no dealpreparations would be made available.
The Sunday Times also reported that Dominic Cummings, the mastermind behind the 2016 referendum campaign to leave the EU and now a senior aide to Mr Johnson, told a meeting of the prime minister's advisers that he had been tasked with delivering Brexit "by any means necessary".
Ministers are preparing for a no-deal emergency budget in the week of October 7, the newspaper added.
Writing in the Sunday Telegraph, new finance minister Sajid Javid said he had ordered no deal preparations in his Treasury Department to be stepped up.
"In my first day in office ... I tasked officials to urgently identify where more money needs to be invested to get Britain fully ready to leave on October 31 – deal or no deal. And next week I will be announcing significant extra funding to do just that," he said.
Mr Javid, a former interior minister, said this would include funding for 500 new Border Force officers.
Mr Johnson has said the Irish backstop, an insurance policy designed to prevent the return of a hard border on the island of Ireland by provisionally keeping Britain in a customs union with the EU, must be removed from any Brexit deal.
It was one of the most hotly contested elements of the divorce agreement his predecessor Theresa May reached with the EU, and opposition to it was a key driver behind the deal beingrejected three times by parliament.
"You can't just reheat the dish that's been sent back andexpect that will make it more palatable," Mr Gove wrote.
"We need a new approach and a different relationship. Critically, we need to abolish the backstop."
Politicians from opposition parties and the governing Conservative Party have threatened to try to block Mr Johnson taking Britain out of the EU without a divorce deal.
The Observer newspaper reported that former finance minister Philip Hammond, who quit last week before Boris Johnson took office, held talks with the opposition Labour Party about how to stop a no-deal Brexit.
Although Mr Johnson has been adamant he will not hold an election before Brexit, his Conservative Party does not have a majority in parliament, are divided over Brexit and under threat of a no-confidence vote when parliament returns in September.
No-deal a 'real and severe' threat - Fianna Fáil
Fianna Fáil has said the threat of a no-deal Brexit is "real and severe" and called for the Government to desist from engaging in "political oneupmanship" with its counterpart in Westminster.
Speaking to RTÉ News, Deputy Darragh O'Brien said: "There is too much at stake here. About 55,000 to 60,000 jobs on this island and thousands of jobs in Britain as well. We are less than 100 days to go to Brexit and we need to be sure that we are prepared as country as much as possible."
His party colleague Fianna Fáil Brexit spokesperson Lisa Chambers said the Government now needs to outline exactly its plans for a hard Brexit.
But Fine Gael's Hidlegarde Naugton pointed out that "British Prime Minister Boris Johnson has stated that he wants the UK to leave with a deal and the Taoiseach is very much looking forward to speaking with him in the near future in relation to how he plans to do that.
"The EU 27 including Ireland have stated that the Withdrawal Agreement is not open for renegotiation and that includes the backstop which guarantees many of the rights around citizens rights, the all-island economy and of course the Good Friday Agreement. We are holding fast on that."
