The Scottish election is a battle between the three parties opposing the SNP - and shy Scots Tories could win it

The big guns at Conservative HQ are willing to throw their weight behind Scottish leader Ruth Davidson

Ruth Davidson, the leader of the Scottish Conservative party, is a hit with the Tory machine in Westminster.

The cover of the Scottish Conservative conference guide lists three pledges for the forthcoming Holyrood election: a “credible and effective” opposition, no second referendum and “protecting family pay packets”. These, the party believes, set it apart from Labour and the Liberal Democrats in the Scottish Parliament. For the curious dynamic of this spring election is that it is more a battle between the three opposition unionist parties than it is about taking on the SNP.

Not prone to unrealistic electoral expectations, the Scottish Tories genuinely believe they will make gains for the first time in more than two decades. So at Edinburgh’s Murrayfield Stadium this weekend, it will fall to Ruth Davidson, the party’s counterintuitive leader, to make good on the positive mood music that she and others have generated for the past few months – that the Tories will win more MSPs than ever before (at least 19 seats) and perhaps even oust Labour as the largest opposition party.

Yet two recent polls show what they have always shown: the Scottish Conservative vote either flatlining or falling. TNS had it on 13 per cent in both the constituency and regional votes, while Survation put the party on 16 and 14 per cent, respectively. If that prediction proves accurate, the Tory group at Holyrood will get smaller rather than bigger.

Of course, the figures could betray the “shy Tory” phenomenon, whereby Scots simply cannot bring themselves to admit voting Conservative. Indeed, veteran Scottish Tory activists believe there is a genuine gap between opinion polling and what is happening on the ground: a more positive reaction to the party, and particularly its leader, than they have experienced in years.

Although Conservative HQ must tire of what many consider hope over expectation, the big guns at Westminster remain willing to help Davidson. The Prime Minister will be at conference, warning of the consequences of Brexit, while the Defence Secretary, Michael Fallon (an Anglo-Scot), will confirm an £136m Scottish contract for the renewal of Trident.

Much is made of Ms Davidson’s influence within the UK Conservative Party. It is said, for example, that she helped to persuade No 10 not to hold a Commons vote on Trident before the Holyrood elections, and she has publicly questioned the chances of George Osborne becoming the next Prime Minister (clever spin, no doubt, but necessary in a political domain that requires all to “stand up for Scotland”).

A collection of essays launched at today’s conference urges the party faithful to “start parking their tanks on unexpected lawns”; in other words, thinking counterintuitively by considering such policies as federalism, a basic income, proportional representation and the adoption of gender quotas for election candidates. In her keynote speech, Ms Davidson will even call on the SNP to ensure that spending on the NHS in Scotland rises. It is all about making the Tories a more “credible” opposition, pragmatic and centrist.

When Survation asked what should happen to the basic rate of income tax (soon to be controlled by Holyrood), nearly 60 per cent either said “no change” or “decrease it by 1p”. But then many Scots voters agree with Tory policies but blanche at the idea of voting for the party. There are modest indications that Davidson is breaking down such ingrained prejudices. On 5 May we will see whether it has worked.