Speaking in London Olympic Park, the Prime Minister is expected to invoke the spirit of Great Britain’s medal-winning team and the patriotism it represented, according to the BBC.
He is set to say Scotland is “part of a major global player” and he urged everyone to vote to reject its move to independence.
“We would be deeply diminished without Scotland. This matters to all our futures. And everyone in the UK can have a voice in this debate,” he is expected to add.
Cameron is also due to warn supporters of the union against complacency. He will describe the UK as a “powerful brand” but add that Scottish independence would “rip the rug from under our own reputation”.
But Scotland deputy first minister Nicola Sturgeon described the speech as “cowardly” and “high-handed”.
The independence debate has frequently focused on economics. In January, Bank of England governor Mark Carney said an independent Scotland would have to cede some sovereignty if it wished to remain in a sterling currency union.