THE new head of the UK civil service has acknowledged the future of the United Kingdom is under threat in his first message to staff.

Simon Case, who was appointed Cabinet Secretary last week, told colleagues a key challenge they faced was “maintaining the integrity of the Union”.

In a leaked internal memo reported by Civil Service World, Mr Case bracketed the issue alongside dealing with the Covid pandemic, the economic recovery and finalising Brexit.

Recent polls suggest support for Scottish independence has grown to around 55 per cent in recent months, as Nicola Sturgeon has been seen to have handed the pandemic far better than the Prime Minister. 

Mr Case’s comments appear at odds with Mr Johnson’s repeated pledge to safeguard the Union by denying Holyrood the power to hold a second referendum.

In January, the PM refused Ms Sturgeon's request for referendum powers, saying the No result of 2014 was, as she had described it, a once-in-a-generation vote.

However Cabinet office minister Michael Gove is reported to be alarmed that another SNP majority win at Holyrood next year could lead to Indyref2.

In the leaked memo, Mr Case said staff would “need to pull out all the stops to deliver what the public expects… in what can fairly be described as challenging times”.

He said: “This includes managing the Covid-19 pandemic, kickstarting the nation’s economic recovery, navigating the transition out of the EU, maintaining the integrity of the union, all while supporting the government to deliver on its ambitious manifesto commitments.

"Our response to the coronavirus pandemic has shown what we are capable of, thousands of you have worked tirelessly over the last few months to design innovative ways of delivering frontline services to our citizens. 

"We must build on this momentum and also demonstrate our ability to act as an effective, evidence-driven, adaptable service. 

“This will be vital as we continue our journey towards becoming a world-leading 21st-Century government machine with people that can unlock the potential of data, invite challenge and remove the obstacles that frustrate us."

Mr Case takes over from Sir Mark Sedwill, who stepped down after two years in the post following reported clashes with Mr Johnson’s controversial senior aide Dominic Cummings.

A former private secretary to Prince William, Mr Case was appointed permanent secretary at No 10 in May, where he headed up the government’s response to the coronavirus.

His comments on the Union could encompass Irish reunification, as the law says a border poll will he held in Northern Ireland if a majority there support leaving the UK to join with the Irish Republic.