Boris Johnson is due to make his first visit to Scotland as prime minister and has called for a renewal of “the ties that bind our United Kingdom”.
During Monday’s visit he will be announcing £300m of new funding for Scotland, Wales and Northern Ireland.
It comes the day after Scottish Conservative leader Ruth Davidson said she would not back his plans for a no-deal Brexit.
Mr Johnson plans on that course if a deal cannot be agreed by 31 October.
Writing in the Mail on Sunday, Ms Davidson said she backed Mr Johnson but would not give her support to a no-deal Brexit.
During his visit to a Scottish military base, he will set out how the new pot of money will help communities in Scotland, Wales and Northern Ireland.
Under the latest Growth Deals plan, the funding will go towards deals in Falkirk, the Islands and Argyll and Bute in Scotland, Causeway Coast and Glens and Mid South West Northern Ireland, and Mid Wales.
The prime minister also plans to go to Wales to meet members of its farming community and Northern Ireland to discuss ongoing talks to restore devolution at Stormont.
Ahead of his Scottish visit, he said: “Our Union is the most successful political and economic union in history. We are a global brand and together we are safer, stronger and more prosperous.
“So as we prepare for our bright future after Brexit, it’s vital we renew the ties that bind our United Kingdom.
“I’m proud to be in Scotland today to make clear that I am a passionate believer in our great Union, and I look forward to visiting Wales and Northern Ireland to ensure that every decision I make as prime minister promotes and strengthens our Union.”
On Sunday, Ruth Davidson, who does not get a vote on Brexit, wrote: “I hope beyond measure that the prime minister is successful in getting an agreement with the EU so he can go back to the House of Commons and get the majority backing he needs.
“He has my full support in those efforts. Where I differ with the UK government is on the question of a no-deal Brexit.”
She added: “When I was debating against the pro-Brexit side in 2016, I don’t remember anybody saying we should crash out of the EU with no arrangements in place to help maintain the vital trade that flows uninterrupted between Britain and the European Union.
“I don’t think the government should pursue a no-deal Brexit and, if it comes to it, I won’t support it.
“I wrote to tell the former prime minister Theresa May that last year and I confirmed my position to her successor when I spoke to him last week.”
Minister of the Union
Mr Johnson’s appointment as prime minister and the possibility of a no-deal Brexit from the EU have brought fresh speculation about the Union’s future.
Scotland’s First Minister Nicola Sturgeon is reviewing the timetable for a possible second vote on Scottish independence and Mr Johnson has been described as the “last prime minister of the UK” by the SNP.
Both Ms Sturgeon and Mark Drakeford, the First Minister of Wales, have told the PM it would be “unconscionable” for the UK to leave the EU without a deal.
Mr Johnson told the first meeting of the cabinet on Thursday that he would be taking the title of Minister for the Union alongside that of prime minister – a move described by a spokesman as a statement of his commitment to strengthening the Union.
The Growth Deals announcement comes after he announced a £3.6bn towns fund over the weekend, supporting an initial 100 towns in England.
Mr Johnson said: “As I said when I stood on the steps of Downing Street last week, it is time that we unleashed the productive power not just of London and the South East but of every corner of England, Scotland, Wales and Northern Ireland.
“Important projects like the government’s growth deals – today backed with £300m new funding – will open up opportunities across our Union so people in every corner of the United Kingdom can realise their potential.”
Scottish Secretary Alister Jack said: “This investment will enable us to build on the success of our existing Growth Deals, which are helping to create jobs and boost local economies right across Scotland.”
Northern Ireland Secretary Julian Smith said: “I am looking forward to working with our partners in Northern Ireland – in particular, I hope very soon, a restored Executive – on how we make the most of this, building on the success we have had agreeing a City Deal for Belfast and the progress we have made on a deal for Derry-Londonderry.”
Welsh Secretary Alun Cairns said: “Wales is the only nation of the UK where Growth Deals have already been announced to cover all of our communities and the prime minister and I are committed to building on the successes of our existing collaborative achievements in both south and north Wales.”