Nick Clegg has warned that “the clock is now ticking” for “the end of the United Kingdom” and that the break-up of the Union is now “more likely than not”. In his first print interview since his appointment in October 2018 as Facebook’s head of global affairs and communications, the former deputy prime minister told the New Statesman: “the Brexit demon has unleashed such an aggressive and regressive right-wing English nationalism… the Conservative Party is converting itself into an English nationalist party.”

Clegg said of Boris Johnson, who is set to become prime minister next week, “the more you see of him, the less impressive he is. With familiarity, he diminishes.” The former Liberal Democrat leader, who lost his seat at the 2017 general election, predicted that Johnson would call an early election in an attempt to prove his political popularity. “He’s going to really scratch away at that itch because that’s all he has got.”

Elsewhere in the interview, conducted by the writer and novelist Edward Docx, Clegg recounts how he overcame his initial scepticism about working for Facebook. During early conversations with Sheryl Sandberg, the company’s chief operating officer, Clegg said: “I’ve spent the last 20 years working and being shouted at and I don’t feel like doing that again.”

When he eventually flew out to California to meet Mark Zuckerberg, he told him: “Your fundamental problem is that people think you’re too powerful and you don’t care.”

However, he describes Zuckerberg as “much maligned” and “unbelievably thoughtful”.

Challenged on allegations that Facebook helped enable Russian interference during the 2016 EU referendum, Clegg claims that “We have no evidence. We have looked for it… And the only thing we can confirm is that they – the Russians – if I can put it loosely – spent $1 on the Brexit referendum.”

Questioned on the Cambridge Analytica scandal, in which the political consulting firm harvested millions of people’s personal Facebook data without their consent, Clegg said: “Crucially, the watchdog has said that no UK Facebook data was involved. So, the Cambridge Analytica data, as much as we can tell, is almost entirely to do with US voters, not UK voters. I think kind of conflating the two is not very... helpful.”

Clegg also defended Zuckerberg’s refusal to appear in front of British MPs on the media select committee. “he’s given evidence to the US Congress, to the European Parliament... He will no doubt give evidence to other parliaments in future. But [the UK] hasn’t actually attracted the attendance of other chief executives.”

The former Liberal Democrat leader, whose party was reduced from 57 seats to eight at the 2015 general election, said the Lib Dems’ improved opinion poll ratings gave the party “a real opportunity to hold the balance of power again”. While refusing to criticise outgoing leader Vince Cable, he said of the party’s current contest: “Jo [Swinson] or Ed [Davey] will give some real energy to it… because there’s an excellent opportunity. In the grand scheme of things for such an old political party, it’s only four years and we’re back in business.”

The full version of Nick Clegg’s interview appears in this week’s New Statesman, out in London tomorrow and nationwide from Friday.