THE Prime Minister will today deliver a pro-Union message his party faithful in Stirling will relish, but tougher questions on where the Scottish Tories go from here on constitutional change have been pushed to the fringe.

Two unofficial meetings will discuss the vexed issue of where the party should position itself beyond next year's referendum – the "line in the sand" for which they thought they were voting when they elected Ruth Davidson as leader, or her later shift to a panel considering further powers for Holyrood.

The conference – bookended by the Prime Minister's visit and a speech by former Labour Chancellor Alistair Darling as part of the Better Together campaign – is being given scant opportunity to consider these issues, with little provision made on the agenda.

David Cameron will be cheered at the Albert Halls as he extols the virtues of the UK's "shared endeavour" from the British soldiers who fought together on the Normandy beaches to the British athletes who competed as a team at last year's Olympic Games.

He will speak of the distinct individuality of the four nations of the UK but also the commonality fostered by their combined efforts, insisting there is "simply no challenge we face today where breaking up Britain is the right answer".

He will tell party members: "Our United Kingdom's history has always been one of shared endeavour; proud in our individual identities but working together for a common good.

"We saw it when our soldiers fought together under one flag on the beaches of Normandy. We saw it when our doctors came together to build our NHS.

"We saw it in the scientific breakthroughs that we made together, from the television to penicillin. And we saw it last summer as athletes from around Britain – no matter where they were from – draped themselves in one flag. And there is still so much more to come."

He will ask why Britons would not want to face the future together, saying: "The future I see for Scotland is part of a dynamic, enterprising, prosperous, compassionate Britain that isn't just competing in the global race but winning in the world – a country where we are pulling together, not pulling apart."

But it is at two fringe meetings that the real debates will take place – a familiar feature of Scottish Conservative conferences. One will link the Tory Reform Group with the Devo Plus project of Reform Scotland founder Ben Thomson.

Another that will give a better sense of the party mood and the appetite for constitutional change will be a Law Society event asking questions that have no place on the main conference floor: "Side-lined or centre stage? Where is the Conservative voice in the debate on Scotland's constitutional future?"

Ms Davison is having to defend herself against criticism for going too fast – committing to a group looking at future Scottish constitutional change.

She is also under some fire from the camp around defeated leadership rival Murdo Fraser for going too slowly – that group's membership has not even been finalised and no date is set for it meeting.

But the biggest criticism bubbling under in Stirling will be that she should not have been going into this area at all.

A senior party source insisted she was approaching the questions in the correct order – seeking views, producing a report, then holding a debate.

Alex Salmond has claimed the Prime Minister should apologise for "fears and smears" about the independence debate and its impact on investments, which he said was completely debunked by a consultants' report this week.

The First Minister also re-issued his challenge to a head-to-head debate on the referendum. "The Prime Minister is the most senior elected politician arguing for a No vote – if he wants to be part of the debate he has an obligation to take part in a debate, so that the people of Scotland can judge," he said.