Boris Johnson has said the union is more important than Brexit in the first TV debate of the general election campaign. The Prime Minister went head-to-head with Labour leader Jeremy Corbyn in the ITV debate, which was broadcast live on STV. Both leaders were asked by a member of the audience whether the integrity of the UK was worth sacrificing for the sake of leaving the EU. It comes after a poll of Conservative party members in the summer found nearly two-thirds of them said they would want Brexit to happen even if the result was Scottish independence. First to answer, Corbyn said the PM's Brexit deal was "about creating a border between the Republic of Ireland and Northern Ireland, and creating a different customs arrangement for Northern Ireland with the rest of Ireland". Johnson responded: "We have a deal that keeps the whole of the UK together as we come of the EU. "And, of course, Jeremy Corbyn and the Labour party, be in no doubt about it, in order to secure power and the keys to Number 10 are going to do a deal, or probably already have done a deal with Nicola Sturgeon and the SNP to form Corbyn-Sturgeon coalition. "The price of that deal ... would be a second referendum on the union with Scotland." Pressed on if the union is more important than Brexit, Corbyn opened by initially replying to "nonsense" suggestions from the PM about a coalition between Labour and the SNP. He said: "There's not going to be a coalition between Labour and anybody else. There are no deals that have been done and there will be no deals that are done." The Labour leader reiterated that his party is against allowing a second independence referendum in the "early years" of a Corbyn government. On the union question, he went on: "Our country is obviously very, very important and we have to bring this business to a close, and that's why we're proposing a trade deal with Europe or staying in - one or the other - as a way of bringing this issue to a close." On the same question, Johnson said: "The union is, of course, the most important thing. It's a fantastic thing." He added: "I listened very carefully as I always do to Mr Corbyn - I didn't hear him say he was going to rule out a referendum on Scotland. Did you?" SNP leader Nicola Sturgeon and Liberal Democrat leader Jo Swinson were excluded from the ITV debate, having lost a legal fight to join it the day before. But both leaders will feature in live interviews on the channel at 10pm, as well as in a six-way debate scheduled for early December. The interview programme on Tuesday night will also include Brexit party leader Nigel Farage and England and Wales Green party co-leader Sian Berry. Responding during the debate, the SNP tweeted: "Boris Johnson is happy to talk about the SNP, but he's too much of a feartie to debate @NicolaSturgeon." The First Minister commented afterwards: "The clear takeaway for Scotland from this debate is that neither of these men should be able to determine Scotland's future. "Jeremy Corbyn can't decide if he is leave or remain and Boris Johnson is determined to take Scotland out of the EU against our will. "Only a vote for the SNP in this election can help Scotland escape from Brexit - and secure our right to choose a better future as an independent country." Swinson posted on social media throughout the debate, stating shortly after the question about the union: "Two questions in, and we've had neither person argue for staying in the EU, and neither person stand up for keeping our family of nations together. Some debate this..." A TV debate featuring four of the Scottish party leaders will be broadcast by STV next month. Nicola Sturgeon, Richard Leonard, Jackson Carlaw and Willie Rennie are all expected to take part in the televised general election debate on December 3. The hour-long broadcast will see the party leaders debate each other directly, with questions also coming from STV News' political editor Colin Mackay, who will be hosting the event. Neither the Scottish Greens, the Brexit Party or UKIP will take part, however STV is planning a series of interviews with party leaders, which will include those from the Brexit Party and Scottish Greens, to be aired at a later date.