VETERAN Ulster politician Lord Trimble caused anger last night by accusing the SNP of "doing violence to Scots' sense of self-identity".

The former Northern Ireland first minister's remarks marred the launch of new referendum group, Conservative Friends of the Union, at the Scottish Conservative Party's spring conference in Troon.

It came after the party faithful had received a wake-up call from Prime Minister David Cameron ordering them to stop being defeatist.

Scots leader Ruth Davidson ended the first day of the conference by launching the pro-Union grouping, sharing the platform with UK Conservative co-chairwoman Baroness Warsi, the party's leader in the Lords, Lord Strathclyde, Welsh Secretary Cheryl Gillan, and Lord Trimble representing the fourth nation of the UK.

Lord Trimble opened his remarks to "fellow Conservatives and fellow Unionists" by saying that many in Northern Ireland were concerned about what was happening in Scotland and wanted the Friends of the Union campaign to succeed.

He said in Northern Ireland opinion was moving away from Nationalism. "I have no doubt that having won the argument there we can win the argument here also," he said, adding that the SNP was trying to take Scotland to another place and a different identity.

The Nobel Peace Prize winner added: "To separate that is to do violence to people's own sense of identity, because being British is part of that sense of identity. We want Scotland to stay in the UK and we think Scotland would be better off in Britain."

Speaking in a conference hall rebranded from the Tories' usual signage to their new Friends of the Union livery, Ms Davidson praised those who had lent their weight to the campaign's launch.

She said: "The next thousand days could determine the future of the country we love for the next thousand years." She cited issues such as the passport we carry, the currency we use and the army that defends us.

"This is not an election where we can change our decision in five years' time. At its simplest, this debate is about who we are and who we want to be. It's about nationality, identity and belonging.

"It's about being Scottish and British and now having to choose between the two, about now letting Alex Salmond take one of them away."

But Lord Trimble's remarks prompted SNP Glasgow MSP Humza Yousaf to say last night. He said: "This is exactly what David Cameron and Ruth Davidson didn't want – their much-promised positive case for the Union hasn't even survived the Tory launch event, and now lies in tatters. It is precisely this sort of negative nonsense that is so damaging to the Tory-led anti-independence campaign.

"Lord Trimble couldn't be more wrong about Scotland. Independence is the broad, inclusive and positive option for Scotland, in which the wide range of identities we have in our modern nation – Scottish, British, Pakistani, Chinese, Polish, Irish and many, many more – can all be reflected and celebrated.

"Lord Trimble appears to know as little about modern Scottish identity as David Cameron does."

Ms Davidson will make her first leader's speech to conference this morning. In it she will stake the Tories' claim to be the only party in favour of cutting taxes.

She will say of the powers coming in the Scotland Bill: "While the new tax powers are still some time away, now is the time to think how they can and should be used. As Conservatives, our view on how they should be used is clear: to cut the tax burden faced by individuals and businesses, leaving more money in the pockets of Scots, encouraging more businesses to expand and to create more better-paid jobs in every corner of our country.

"Clearly the scope for cutting income tax will depend on the economic climate and the future state of public finances.

"But let there be no doubt – lowering the overall tax burden is our ambition."