Liz Truss has been challenged to act immediately on the cost-of-living crisis as Nicola Sturgeon congratulates the new Tory leader and next prime minister.

Scotland’s First Minister said she will seek to build a “good working relationship” with Ms Truss despite “deep” political differences.

Their relationship became a key talking point in the Tory leadership contest after Ms Truss said she would ignore Ms Sturgeon.

Ms Truss will formally become prime minister on Tuesday when she meets the Queen at Balmoral after defeating former chancellor Rishi Sunak with around 57% of the vote.

Ms Sturgeon said on Twitter: “Congratulations to Liz Truss. Our political differences are deep, but I will seek to build a good working relationship with her as I did with the last 3 PMs.

“She must now freeze energy bills for people & businesses, deliver more cash support and increase funding for public services.”

Ms Truss – the current Foreign Secretary – is expected to announce cost-of-living support, which could include freezing energy bills, during her first week in the top job.

Scottish Conservative leader Douglas Ross is among the Tory MPs congratulating Ms Truss on becoming Tory leader and next prime minister.

He urged the party to unite to tackle the country’s “big challenges” following the leadership contest.

He said both Ms Truss and opponent Mr Sunak should be “proud” of the campaign and their engagement with Tory party members.

However, he added: “Now that the leadership election is over, it is time for the whole of the Conservative Party to come together to tackle the big challenges our country faces.

“Throughout her political career, Liz Truss has shown herself to have a record of delivery, whether that was in removing US tariffs on whisky and cashmere or in managing the UK’s robust support for Ukraine both before and following the Russian invasion.

“I look forward to working with our new leader and prime minister as she continues to deliver for Scotland and the whole of the UK at this most challenging of times.”

A leadership expert, however, has sent a stark warning to Ms Truss that her decision-making could define her time at No 10.

Dr Christian Harrison, from University of Scotland (UWS), said: “The choices she makes when it comes to the cost-of-living crisis, rising energy bills, strikes in the public sector and relating to the war in Ukraine may irreversibly shape how her time as prime minister is perceived.

“It will also be very interesting to see how Sir Keir Starmer adapts his approach as Labour leader, as she makes these key decisions.

“He will need to explain not only what he would do differently, but also why it is better, and demonstrate that Labour provides a clear alternative as we approach the next election.”

Political opponents from Scottish Labour and the Liberal Democrats have criticised the result, with both leaders Anas Sarwar and Alex Cole-Hamilton saying the appointment is set to be “more of the same” as Boris Johnson’s tenure.

Scottish Greens co-leader Lorna Slater said the result is “terrible news” for Scotland and the environment.