NICK Clegg has admitted fighting a second Scottish independence referendum would be very difficult given the “compelling case” for a majority of Scots who want to remain in the European Union but are being taken out of it against their wishes.

In a significant intervention in the post-Brexit vote constitutional debate, the former Deputy Prime Minister and staunch Europhile warned, towards the end of the Brexit process, of a “very serious clash among the constituent parts of the United Kingdom”.

Speaking at a Westminster press gallery lunch, the former Liberal Democrat leader explained: “If the clash becomes a clash about the stated opinion of English voters that they want to leave the EU compared to the stated opinion of Scottish voters that they want to stay, it’s going to be incredibly difficult…to say to Scottish voters that they should swallow their reservations and vote for the Union nonetheless.”

He went on: “I’m a Unionist. I don’t like Nationalism. Nationalism/chauvinism is a profoundly illiberal creed, so it really distresses me this idea that it’s going to be very difficult to mount a powerful argument when there is such a compelling case for those who say, look, it’s not our choice…we have been forced by events entirely beyond our control. It’s going to be really tough.”

Ahead of the EU referendum vote in April, Mr Clegg claimed that if the UK were to vote for Brexit, then it would have “no empire, no Union and no special relationship.”

He was asked, given the result of the June 23 vote, when Scotland voted 62 per cent to 38 per cent to remain, if he still believed it would become independent and cause the break-up of Britain.

“Well, we haven’t left yet,” declared the Sheffield MP.

“I have been somewhat nonplussed by the people who said over the summer: ‘The sun hasn’t fallen on our heads.’ We haven’t left; it hasn’t happened yet. Things will feel very different when we do finally leave and it depends massively on what terms that we do leave on.”

He said that the country was in a “phoney phase” between the vote and the final settlement but warned that our continental counterparts would not capitulate easily.

“I was in Berlin last week and speaking to a number of senior folk in the political world in Germany. We should be under no illusions that however favourably they might be disposed to us, however much they wish it hadn’t happened, however Anglophile they might be…at the end of the day they are going to be as flinty and hard-headed as anybody else in the remaining membership of the EU, that their first and absolute, almost existential, priority is to stop Brexit being the catalyst for the wider unravelling of their club; of course, it is.”

He suggested that anyone who thought Britain was going to have its cake and eat it, that it would negotiate to keep all the nice bits about the EU and discard all the bad bits, needed to be more hard-headed about the realities the country faced.

“So, therefore, when all this pans out, when it becomes obvious to the Scottish people, the British people, particular to those communities in the UK who voted overwhelmingly to stay, given there’s no neat way of squaring the circle of that fundamental contradiction of the Government’s approach to free trade, on the one hand, and untrammelled sovereignty, on the other, then it will, maybe with a delayed timetable, nonetheless provoke a very serious clash among the constituent parts of the United Kingdom.”

The former DPM also predicted leading Brexiteer Liam Fox, would quit the Cabinet "in a huff" within 18 months in protest at Theresa May's attempts to get Britain out of the EU.

"He doesn't have a job and he doesn't appear to have realised that yet,” claimed Mr Clegg. “If the United Kingdom doesn't leave the customs union, which apparently is still an open question in Whitehall, then he is heading a department without purpose because he cannot negotiate all these fantastic trade deals with Papua New Guinea and Tanzania and China and India and Australia.

"There's only 15 per cent of British trade goes to countries which are outside the European Union or with which we don't have a European trade deal or in the process of having a European trade deal. So this idea that there is these Elysian Fields of unbridled 19th century trade waiting for us, where apparently everyone will give us exactly what we want even though we'll be a fraction of the size of what we were when we were negotiating partners of the EU, it's a nonsense.”

The former party leader added: "The poor chap; if they decide not to quit the customs union, it really will be a little embarrassing because his department will have nothing to do. Even if they decide to quit the customs union he still doesn't have anything to do."

Mr Clegg also predicted that Britain could have a government of “national unity” within five or 10 years as voters lost faith in the politicians' ability to solve Britain’s problems and the Tories steered the country into a “dead-end”.