Speaking at the party's spring conference in Troon, Cameron told his Scottish allies they have been too timid, The Guardian reported. He said that has allowed the Scottish National Party to become the dominant political force.
"I want to demonstrate that this is a party with a proud, patriotic message: Scottish and British," the prime minister said. "But our long-term future depends on more than that, on showing how our values connect with the values of Scotland."
Scotland was for decades a Labor Party stronghold. After the SNP won an absolute majority in the Scottish Parliament last year, First Minister Alex Salmond began pushing for a referendum on independence.
The Conservatives now hold only one Scottish seat in the British Parliament and 15 of the 129 seats in the Scottish one. The party is No. 3 in Scotland after the SNP and Labor.
Polls have suggested independence does not have majority support in Scotland. Salmond wants the vote to be held in 2014, while Cameron is pushing for an earlier one.
"I'm here today to argue that this is our moment -- if we are bold enough -- to come back stronger," Cameron said.