The Tories and their rocky relationship with devolution
The leader of the Scottish Conservatives has put forward a plan for Scotland to be able to set its own income tax in the event of a 'No' vote in the September's independence referendum.
Ruth Davidson said Scotland's "pocket-money parliament" needed to be reformed and given more devolved powers.
But the Conservatives haven't always been so keen on giving more powers to Scotland.
Here, we take a look back at fifty years of the often rocky relationship between the Conservatives and devolution.
In March 1968, Conservative leader Edward Heath committed the party to some form of Scottish devolution in a statement known as the Declaration of Perth.
He said: "It is pledged to give the people of Scotland genuine participation in the making of decisions that affect them - all within the historic unity of the United Kingdom."
In doing so, the Conservatives became the first mainstream UK political party to propose the creation of a devolved Scottish assembly.
The move was partly in response to the rise of the SNP, who had their mainstream breakthrough in 1967 when Winnie Ewing won the Hamilton by-election.
Margaret Thatcher dropped the Conservatives' pro-devolution policy in 1976, causing the resignations of the shadow Scottish secretary, Alick Buchanan-Smith, and the shadow minister of state, Malcolm Rifkind.
However, the discovery of North Sea oil in 1970 had increased momentum and support for devolution within Scotland.
The Labour government was vulnerable to pressures from the burgeoning SNP, which won 11 seats in the October 1974 election, so a referendum bill which would have set up a Scottish Assembly successfully went through parliament.
In the referendum, on 1 March 1979, Scotland voted in favour of devolution by 52% to 48%, but only 33% of the total electorate voted in favour - less than the 40% required for victory.
When the referendum was lost, the Conservatives, supported by the SNP, tabled a motion of no confidence in the Labour government. The resulting general election would see a victory for Margaret Thatcher and the Conservatives, putting devolution off the political agenda at Westminster for nearly two decades.
The Conservatives defined themselves as the anti-devolution party in the run-up to the Labour-backed 1997 referendum. The Tories stressed that they regarded devolution as a back-door way of ending the Union, and campaigned vigorously against it.
However, some members of the Scottish Conservatives began to see devolution as inevitable.
Annabel Goldie, then chairwoman of the Scottish Conservatives, speculated that the Scottish party wouldn't take a collective view in the referendum, allowing individual members to campaign for Yes or No as they wished.
The referendum saw 74% of voters in Scotland agreeing that there should be a Scottish Parliament.
The new Scottish Parliament
In 1999, both the UK and Scottish Conservatives said they were committed to making a success of the new Holyrood parliament.
In 2001, David Davis argued that Scotland should have powers over areas such as income tax and a share of oil revenues, but this idea didn't gain traction within the UK party.
In 2007, Annabel Goldie, by then the leader of the Scottish Conservatives, said her party was committed to making the current devolved powers work to nullify calls for independence.
She said: "I firmly believe that if the Scottish people see that devolution is delivering for the country then the calls for independence and isolation will recede."
Road to referendum
Ms Goldie's expectations were confounded, however, when the SNP won a majority in the Scottish election on 2011, meaning there would be a referendum on Scottish independence.
In March 2013, Scottish Tory leader Ruth Davidson set up a commission to look at further devolution, saying her party was "committed to a new path; more responsibility for the Scottish Parliament and a strengthening of devolution".
This was despite Ms Davidson having previously described proposals for new Holyrood financial powers beyond the recent Scotland Act as "a line in the sand" which she was not willing to cross.
The commission report, published in June 2014, set out proposals for Scotland to be given full powers over income tax, which it said would allow Holyrood to raise 40% of the money it spends.
Giving her backing to the recommendations, Ms Davidson said: "We believe the people of Scotland should have good reasons to be passionate about wanting to remain within this Union.
"That is why it's imperative to offer voters in September a positive vision of how our nation can progress and have a bigger say within the UK."
Will plans for further devolution happen, or will the final destination of devolution be full independence for Scotland?
Only time will tell.