AN air war over economic investment has broken out with Nicola Sturgeon accused of rushing out an announcement on ferry jobs in an attempt to overshadow George Osborne’s trip to Scotland with major announcements on defence and North Sea gas jobs.

The Chancellor, visiting Faslane, hailed as a “massive boost” to Scotland and the defence industry a £500 million UK Government investment linked to Trident renewal, which will safeguard almost 7000 defence jobs.

Later in Aberdeen, he hailed the £3 billion announcement by Danish firm Maersk to develop the Culzean gas field, the largest to be discovered in the North Sea for a decade. This will secure 6000 jobs and create 400 more.

The announcements showed the strength of Scotland being part of the United Kingdom, insisted Mr Osborne.

But the First Minister, coincidentally, turned up in Port Glasgow to announce the local Ferguson Marine shipyard was the preferred bidder for a £97m contract to build two new ferries, safeguarding 150 jobs and creating new ones.

She said the contract “underlines our commitment to creating the vital jobs needed to boost local economies and help stimulate growth across Scotland”.

Derek Mackay, the Scottish Transport Minister, stressed how the Ferguson announcement proved “Scottish shipbuilding can succeed in a competitive market”.

But a senior Conservative source told The Herald it was “curious” that Ms Sturgeon had sought to “fast-forward” the Ferguson announcement, which had been expected later this month.

“Anyone would think she was trying to grab a share of the limelight,” he mused.

But a spokeswoman for the SNP Government denied there was any attempt to engage in a political spoiler to deflect attention from Mr Osborne’s Scottish visit.

“Confirmation of the preferred bidder has been expected for some time and the First Minister’s visit was confirmed last week; long before we even knew of a visit by the Chancellor,” she insisted.