Tory leadership debate – live: Johnson refuses to say whether he would resign if Brexit deadline is missed as he flounders over US diplomatic row

The head-to-head ITV debate between Boris Johnson and Jeremy Hunt will kick off in exactly 20 minutes - we’ll be bringing you all the action live.

Stand by - the Tory leadership debate between Boris Johnson and Jeremy Hunt is about to get underway...

Boris Johnson is first to speak.

He says the country faces a "momentous choice" between the "same old can-kicking approach" to Brexit and someone who will take Britain out of the EU by 31 October whatever the circumstances.

In his own opening statement, Jeremy Hunt says he would use his experience as an entrepreneur to fire up the economy and invest in public services. He is subtly contrasting his cabinet experience with that of Boris Johnson. 

Hunt says polls show he is the public's first choice for prime minister and speaking directly to voters, says he will be be their prime minister regardless of who they voted for.

The first question comes from someone who says he wants to see Nigel Farage as prime minister. He asks whether the candidates can guarantee Brexit by 31 October. 

Hunt says no one should promise something they cannot deliver. He says the only way to guarantee Brexit by that date is to secure a new deal with Brussels, and that he is the person to do that.

Johnson says leaving by 31 October is crucial to avoiding "haemorrhaging" trust in politics. He says he would make the EU understand that he is prepared to leave with no deal and would deliver Brexit by 31 October whatever happens.

Hunt asks Johnson if he would resign if he does not deliver Brexit by 31 October. He refuses to answer.

Laying into Hunt, he says another delay means "forfeiting trust with the electorate and undermining our negotiating position in Brussels".

Johnson says he does not want the EU to know whether he would be prepared to resign, as this would strengthen their hand.

Hunt goes in hard, saying Johnson is willing to put the country's neck on the line but not his own. "That is not leadership," he says.

Boris Johnson says fears of no deal have been "escalated in public discourse". 

Hunt disagrees, saying the impact of no-deal on businesses would be "very serious" but that he has a ten-point plan for helping the UK cope.

Johnson says only a "badly-handed" no-deal Brexit would be costly and that it would be "vanishingly inexpensive" with the right preparation.

Hunt attacks Johnson for claiming that WTO rules mean the UK would not have tariffs if it left the EU without a deal, saying this is is "totally unrealistic".

He says:

"Getting details like that wrong is fine for a newspaper column but if you're prime minister that is people's jobs at stake."

Johnson is getting angry. He responds by calling Hunt "defeatist" and "someone on the other side of the argument for so long".

Hunt has a good response, telling Johnson: "We will not leave the EU just with optimism".

Jeremy Hunt tells his rival:

"Being prime minister is about telling people what they need to hear, not just what they want to hear. The difference between you and me is that you are peddling optimism."

Boris Johnson responds:

"I think this country needs a bit of optimism, frankly."

The candidates are asked if they would be willing to prorogue parliament to force through a no-deal Brexit.

Hunt say no, because the last time it happened there was a civil war.

Johnson refuses to rule it out, saying it would be astonishing to do so because it would further weaken the UK's negotiating position.

Here's the clip of that first attack by Hunt on Johnson: