David Cameron will today insist the Scottish defence industry has a brighter and more secure future if the country remains part of the United Kingdom.

The Prime Minister's arrival in Scotland coincides with the publication of a UK Government response to a Commons report, which clearly warns that if Scotland were to leave the UK, then it could not be guaranteed future British warship contracts.

Making his first visit north of the Border in six months, Mr Cameron will host one of his PM Direct events at the offices of a Scottish-based defence contractor, when he will claim defence jobs in Scotland are more secure because of the Union and that being part of the UK "opens doors for the Scottish defence industry around the globe".

"Defence matters and defence jobs matter," he declared last night.

The PM added Scotland had a world-renowned and highly skilled defence sector that employed more than 12,600 people, with annual sales in excess of £1.8 billion. It played a key role in equipping and supporting the UK armed forces, "from iconic industries like shipbuilding on the Clyde and Rosyth to cutting-edge, high-tech manufacturing".

He said: "Being part of the UK opens doors for the Scottish defence industry around the globe. When we sell Typhoons overseas, this benefits jobs and growth for companies making components in Scotland.

"Scotland counts for more on the world stage because it is part of the United Kingdom and Scottish defence jobs are more secure as part of the United Kingdom.

"I remain absolutely committed to the defence of the United Kingdom and to the future of defence jobs in Scotland. Defence matters. We are stronger and safer together."

However, Angus Robertson, the SNP's defence spokesman, said Mr Cameron was making a mistake by focusing on defence.

He claimed: "It is the most enormous blunder for the No campaign to place Trident at the centre of the referendum debate. The [Scottish] Parliament and 80% of the people of Scotland want to get rid of Trident and the obscene waste of up to £100bn it represents at a time of austerity and savage welfare cuts from Westminster.

"David Cameron should be using this visit as his opportunity to apologise for Westminster's betrayal of Scotland's communities and its constant broken promises on defence."

Last month, Philip Hammond, the UK Defence Secretary, issued a stark warning the UK Government would not build a new generation of warships on the Clyde if Scotland left the UK.

This was echoed this morning by the Coalition's response to the Scottish Affairs Committee report entitled "Separation shuts shipyards".

It pointed out that, except during the World Wars, the British Government had "never built a complex warship outside the UK". It noted that the main investment decision on the planned Type 26 Global Combat Ship would be made by the middle of the decade – after the 2014 referendum – and would be worth billions of pounds and support thousands of jobs.

The Coalition response pointed out that, under EU procurement rules, there was an exemption for warships, which meant they could be built in the UK on grounds of national security and avoid outside competition. It noted: "As this exemption is currently applied, Scottish shipyards would not be eligible to bid for contracts to build complex warships for the Royal Navy if Scotland was to become independent."

Ian Davidson, the Labour chairman of the committee, said the Coalition had made it clear it wanted to retain the capacity to design and build complex warships within the UK and use the EU exemption to avoid putting such work out to international competition.

"In these circumstances it is difficult, if not impossible, to see how the Clyde yards can have any long-term future in a separate Scotland," he added.