MAIDSTONE, England/LONDON (Reuters) - Prime Minister Boris Johnson and opposition Labour leader Jeremy Corbyn clashed over Brexit on Friday in the last televised debate before next week’s election that will determine the path for Britain’s departure from the European Union.

Six days before Britain votes in its second national election in less than three years, the debate was seen as the last chance for Corbyn to squeeze Johnson’s lead in the polls, which mostly point to victory for the prime minister.

A snap poll by YouGov found 52% of viewers thought Johnson had won the debate.

The two leaders set a combative tone over how to leave the EU and in their very different offers for domestic policy - “socialism carried out in a democratic way” from Corbyn, or “one-nation Conservatism” that will not “rack up debts” from Johnson.

More than three years after Britain voted to leave the EU, the Dec. 12 election will determine when, how and even whether Brexit happens.

Johnson ridiculed Corbyn’s support for a new referendum in which Corbyn has said he would remain neutral, while the Labour leader said the prime minister’s pledge to “get Brexit done” actually meant years of trade talks.

“We have ample time to get on and build a new free trade partnership, not just with the EU but with countries around the world,” Johnson said in the BBC television debate.

But Corbyn countered that it would take the government seven years to negotiate a trade deal with the United States and said business could not live with the uncertainty that Britain might still leave the EU without a deal next year.

Polls show Johnson’s governing party is well ahead of Labour. A Panelbase survey on Friday showed the Conservatives extending their lead slightly over the opposition party to nine points, up from eight a week ago.

Johnson, who renegotiated a new divorce deal with the EU in October, has promised to “get Brexit done”, a slogan he has repeated constantly during campaigning to try to win over Labour supporters who backed leaving the bloc, and those who are simply fed up of the political haggling over the issue.

Britons voted by 52%-48% in 2016 for Brexit but parliament has been stuck in deadlock over the way forward. If Johnson wins the majority he says he needs, Britain will leave by Jan. 31 and then seek to secure a trade deal with the bloc by the end of 2020.

DAMAGING DOSSIER

Keen to land a blow, Corbyn doubled down on an earlier attack on Johnson, calling his Brexit promises a fraud and saying his deal would simply be the start of years of “painful negotiations and broken promises”.

The Labour leader waved at him documents he had unveiled earlier in the day, which he said showed the divorce deal would lead to customs declarations and security checks between Britain and Northern Ireland, a direct contradiction of Johnson’s statements that it would not create any barriers.

“How about the prime minister showing a degree of honesty about the arrangements he’s actually made with Northern Ireland,” Corbyn said. “It is a question of openness.”

Johnson said the document was “complete nonsense” and his team said they believed he had weathered the attack successfully.

Both were taken to task over accusations of prejudice in their parties, and questioned over their approaches to Britain’s much loved public health service and their stance on security, a week after another terror attack hit the capital.

But with less than a week until the election, it looks as though many people are still undecided and the Conservative lead, so far, intact.

Sterling this week hit a 2-1/2-year high versus the euro and a seven-month high against the dollar on expectations that the Conservatives will win the election.

“Given the Conservatives went into this debate in the lead, they will hope the lack of a knockout blow means they can maintain this until voting day,” said Chris Curtis, YouGov’s Political Research Manager.