MINISTERS are under pressure to explain why a ferry company owned by the Scottish Government is set to share in the management of an army-run port on the south coast of England.

Ferry operator CalMac's parent company, David MacBrayne Ltd (DML), is a partner in a firm which has won preferred bidder status for the management of Marchwood Military Port, across the estuary from Southampton.

It is one of biggest military bases in the south of England, home to the Royal Fleet Auxiliary and vessels run by the Royal Logistics Corps. It is currently operated by the RLC's 17 Port and Maritime Regiment.

The news of the potential takeover by Solent Gateway Ltd - a joint venture between DML and Grimsby-based GBA (Holdings) Ltd - has angered many in Hampshire, who had been expecting a jobs boost from a rival bidder's plans.

North of the border, opposition politicians say ministers should have informed MSPs about the "change in strategy" from DML, a publicly owned company.

Labour's shadow transport minister, Highlands and Islands MSP David Stewart said: "This appears to be a departure from the usual business model pursued by the group.

"Given that it is taxpayer cash being used I believe that the Scottish Parliament should have been informed of this change, and would urge the Minister to clarify this change in strategy as soon as possible."

It had been widely assumed in the south that Associated British Ports would be named as the preferred bidder, with its network of 21 ports across England, Wales and Scotland. It had drawn up plans to turn part of the Marchwood site into a car storage facility employing about 400 people.

According to the MoD there is "a period of final engagement between MOD and Solent Gateway Limited" but the new operator should take over in the autumn. Little is known about Solway Gateway's plans.

However, DML said they had considerable experience in the sector, having operated 24 of the ports CalMac serves in the Clyde and Hebrides since 2007.

The MoD has said the new arrangement is expected to generate profits and cut costs.

A Scottish Government spokesman said minsters were always pleased to see Scottish companies succeeding in a competitive marketplace

He said: "Although DML's core market is Scotland, the company is keen to explore opportunities elsewhere which align with its business expertise and public service ethos.

"This strategy is supported by the Scottish Ministers as sole shareholder, who are particularly pleased to see DML extend its public service role."

Martin Dorchester, chief executive of DML, said the bid was a "clear reflection of the way the company is successfully working to diversify our business base giving the whole company greater strength and depth".