SCOTTISH independence and a push for Irish reunification would pose "real threats" to the 300-year-old Union if there were a no-deal Brexit, Liam Fox has warned.

The International Trade Secretary and leading Brexiteer, who is supporting Jeremy Hunt as the next Conservative leader and Prime Minister, was challenged to say whether a badly handled EU exit without a deal could lead to Scottish independence and a border poll to reunite the island of Ireland, which would end the United Kingdom.

READ MORE: Philip Hammond warns Conservative contenders of no extra cash for their spending pledges in event of no-deal Brexit

He replied: "We know they are both real threats, there's no point in pretending they're not there.

"And therefore we have to put in place the details of what a no-deal would look like, including how we protect crucial industries like fishing and farming and how we deal with small businesses,” he told BBC Radio’s Today programme.

"It's not good enough to simply say we are going to have a no-deal; we need to prepare for it. That's what government is all about," insisted the Scot.

Boris Johnson has pledged Britain would leave the EU by October 31 "do or die". Yet he also said he believed the chances of a no-deal Brexit were a "million-to-one against".

READ MORE: Majority now support early vote on second Scottish independence referendum

Mr Hunt, meanwhile, has argued that October 31 is a "fake deadline" and that if a deal is close he would be prepared to ask for a delay. However, the Foreign Secretary has also made clear that he would take Britain out of the EU “come what may,” if securing a deal with Brussels was not possible.

Both candidates have been emphasising their Unionist credentials in the run-up to this Friday’s Scottish hustings in Perth.

Mr Hunt has insisted he is a Unionist “to my finger-tips” and would never allow anything to jeopardise the United Kingdom.

Mr Johnson has also made clear he is a committed defender of the Union and argued that a well-performed Brexit could "cement and intensify" the UK and “spike the guns” of the SNP.

The former London Mayor at the weekend said he would add “Minister for the Union” to the PM’s title, would set up a No 10 unit to “stress-test” policies to ensure they benefited the Union and made clear he would keep the 40-year-old Barnett Formula, by which additional public spending is distributed to Scotland; a policy he previously criticised.