Boris Johnson insists he'll agree a new trade deal with the EU by the end of next year if he wins next month's UK general election.
The British Prime Minister and UK Labour leader Jeremy Corbyn have gone head to head in the first live TV debate of the campaign there.
Mr Corbyn, meanwhile, made a pledge to hold a second EU referendum within six months of forming a government.
Mr Johnson made clear he believed Britain's future relationship with the EU could be sorted out by the end of 2020 - and warned of more "dither and delay" under Labour.
He said: "We have ample time to do a fantastic free trade deal with our friends and partners in the EU cause we're already in a state of perfect alignment - both for tariffs and for quotas".
Mr Corbyn promised to deliver on the results of a second EU referendum if his party wins.
"Our government will abide by that result - I will carry out the result of that referendum.
"There will be a genuine choice put before the people of Britain to make their decision, and we will carry it out".
Boris Johnson challenges Jeremy Corbyn on whether he will campaign for remain or leave in a future Brexit referendum, whilst Jeremy Corbyn accuses Boris Johnson of not being honest about his timelines #ITVdebate pic.twitter.com/sSPS3RrGyY
— ITV News (@itvnews) November 19, 2019
Mr Corbyn said Mr Johnson's claim that he can "get Brexit done" by the end of January was "nonsense".
"What he is proposing is a trade deal which will take at least seven years to negotiate whilst at the same time saying he will negotiate a special trade deal with the European Union.
"The two things are actually incompatible."
Mr Johnson claimed his Brexit deal will allow the whole of the UK to come out of the EU, adding: "Northern Ireland is part of the customs territory of the UK. It's there in black and white."
Scottish Independence and the NHS were also discussed throughout the course of the hour-long debate.
Additional reporting: IRN