Theresa May has said Britons are "one people" at heart as she called for Scots to reject "old tribal politics" and vote for the Conservatives in the General Election.
The prime minister said "too often in the past" UK governments have "tended to devolve and forget" as she pledged to deliver for the whole of the UK.
"The government I lead will put that right," she said, adding: "We'll make the institutions of our United Kingdom a force for good across the whole UK."
Mrs May urged Scots not to think about who they voted for in the past, calling on them to instead consider "who you want to lead our country in the future, who will get the best deal for the whole of the UK from Brexit".
Her speech to Conservative activists in Edinburgh came a day after she launched the party's manifesto, which has been condemned by Labour as a "savage attack on pensioners" as the Lib Dems branded Mrs May a "lunch snatcher" for ending free school meals.
Mrs May called on voters to support her, saying: "It is time to come together in the national interest, united in our desire to make a success of Brexit."
The prime minister also repeated her opposition to a second vote on Scottish independence, saying: "This is a time to pull together, not apart."
Mrs May took a dig at Scotland's First Minister Nicola Sturgeon as she said the "UK government already employs more civil servants in Scotland than the Scottish government does".
Mrs Sturgeon issued her call for a second independence referendum after Scots voted by a margin of 62% to 38% to remain in the European Union last June - in contrast to the overall 52%-48% UK vote to Leave.
Mrs May criticised Jeremy Corbyn's statement that a repeat Scottish referendum - after 2014's vote to remain in the UK - would be "absolutely fine" and attacked the Labour leader's ability to keep the UK united.
"Jeremy Corbyn is too weak to stand for our union even if he wanted to," she said.
The prime minister also warned that depending on the results of the General Election, the Labour leader could be "propped up by the Scottish nationalists".
She added: "A vote for any other party is a vote to weaken our Union, to weaken our negotiating hand in Europe and to put our future prosperity and security at risk."
The PM was speaking after her party's Scottish leader, Ruth Davidson, made a direct pitch to Labour voters disillusioned under the leadership of Jeremy Corbyn.
"Let me do a job for you," Ms Davidson told them.
With recent elections showing Scots coming back to the Conservatives, Mrs May told voters: "Come with me as I lead Britain. Strengthen my hand as I fight to strengthen our Union."
The Conservative leader also said "unlike other parties we are being upfront and honest with British people about the scale of the task we face".
She added: "Because leadership means being straight with people about the challenges ahead and the hard work required to overcome them and that is what this manifesto does."
Mrs May insisted "only the Conservative and Unionist Party has the strength and credibility to stand up to the nationalists and defend our United Kingdom".