RUTH Davidson has warned that hoarding too many powers in London could cause "cracks" in the Union.

Davidson will use her speech to the UK Tory conference today to admit the UK has become too "London-centric".

She calls for “more Union", with a greater spread of civil service and public bodies across the UK.

Davidson admits that even after 20 years of devolution London dominates the UK in a way that other world capitals such as Washington DC or Berlin do not.

The Scottish Tory leader warns her party that supporters of independence would use those failings to "pull us apart for good". She will say: "Devolution of power has transformed our nation for the better.

"It has put power closer to people. But at the same time – while we’ve built vigorous new devolved structures, we’ve not done enough to nurture that which binds us.

"As the Prime Minister said in Scotland earlier this year, all too often, Whitehall devolves and forgets. And the danger is that we become a country that stays together, but lives apart.

"With the cracks exploited by those who would pull us apart for good."

Davidson argues that more UK institutions and public servants must be moved away from London to other cities.

In her speech to the conference in Manchester, Davidson says: "Let’s absolutely press on with more devolution. But it’s time for a bit more Union too."

Davidson adds: "But the truth is: for all the devolution of power in the last 20 years, our Union continues to be far too London-centric.

"Compare us to our friends around the world. New York’s global status doesn’t diminish Washington’s political clout, LA’s creative output, or Silicon."

SNP Westminster leader Ian Blackford hit back saying the Tories could not be trusted to devolve powers away from London.

He said: “Ruth Davidson’s comments are nothing more than a diversion and an attempt to take the focus away from the complete failure of the Tories to deliver for anywhere but south-east England."

Davidson's speech comes after Tory MSP Murdo Fraser said the party’s 13 Scottish MPs should distance themselves from its UK leadership.

Fraser campaigned to scrap the name Scottish Conservatives in a bitter contest with Ruth Davidson to lead the party in 2011.

However, he has now reopened the row today as the UK Tory conference opens.

He stopped short of repeating his call for a centre-right breakaway from the UK Tories. But he said the party must embrace a “nationalist Unionism” and “Liberal Unionism".

He said such labels would give the Scottish party a separate centre-right identity to their colleagues down south.

Fraser made the remarks in an article for the online centre-right blog Conservative Home.