Image copyright Getty Images Image caption Theresa May is expected to visit Scotland on Thursday

The prime minister is to announce a review of UK government departments to make sure they work in the best interests of devolution.

Theresa May will make the announcement during a visit to Scotland this week in one of her final visits as prime minister.

It was described as a "desperate act" by Nicola Sturgeon.

The review will be chaired by Lord Dunlop, the former Scotland Office minister.

It will ensure that all of the UK government's structures - including government departments - are co-operating to ensure devolution works.

The move is seen as a necessary step, particularly after the UK's departure from the European Union.

Scotland's first minister has said she wants to hold a second referendum on Scottish independence if the country is taken out of the EU.

And Scotland Secretary David Mundell has warned that a no-deal Brexit could "threaten the continuance" of the UK.

Both Jeremy Hunt and Boris Johnson have committed to strengthening the union, but neither has ruled out leaving the EU without a deal.

Image copyright STV/BBC Image caption Former Scotland Office minister Lord Dunlop will lead the review

When news of the review was reported by The Scotsman on Tuesday night, there was concern that it could stray into devolved areas - but Number 10 made clear it was not the case.

Nicola Sturgeon said it was a "desperate act by a prime minister who has shown zero respect for the Scottish Parliament during her time in office".

"It's for the Scottish people - not a Tory PM - to consider and decide what future we want for our parliament and country."

Scotland Office minister Lord Duncan told the BBC's Good Morning Scotland programme that Ms Sturgeon "would say that sort of thing, wouldn't she?"

He added: "What we're doing right now is examining how devolution works here.

"Time and time again I've listened to the first minister saying that the UK government isn't working for Scotland. The UK government is working for Scotland and it wants to make sure that it is working as best as it can, hence this review - a simple straightforward way of making sure devolution is working as best as it can be."

The SNP's leader at Westminster, Ian Blackford, later described the review as a "farce" at Prime Minister's Questions, and claimed that: "The real legacy of this prime minister is shutting down Scotland and ignoring the will of the Scottish Parliament. The Tories have never supported devolution and it's clear they never, never will."

Mrs May responded by saying: "There is only one party in this House who wants to stop devolution in Scotland and that's the Scottish National Party".

The prime minister's visit to Scotland on Thursday will come the day before a Conservative leadership hustings in Scotland.

On Sunday, Mr Johnson outlined plans for a unit in Number 10 which would "sense-test and stress-test" every policy for the results it would have on the union.

And he said the next prime minister should be "minister for the union", a position which was "cost-free but symbolically significant".

Meanwhile, Mr Hunt said he would ensure the UK left the EU in a way that protects the union.