THE future strength and structure of the Royal Navy must be driven by "operational need" and not the Treasury, a Westcountry defence expert has warned.

Steve Bush, editor of the Liskeard-based Warship World, says that despite the Navy's pivotal role in Afghanistan, the Senior Service could be vulnerable in any post-election defence spending review.

Writing in his annual book, British Warships and Auxiliaries, which is published today, he says its case is not helped by the "dwindling" link between the public and the Navy and the fact that it is "operating out of public sight and over the horizon".

"For much of the time the troops on the ground have been Royal Marines – a part of the Royal Navy.

"Many of the helicopters in Afghanistan are aircraft of the Fleet Air Arm, the Harriers deployed at Khandahar have for many months of the year been provided by the naval strike wing.

"Many of the medical staff and support staff are from the Royal Navy.

"Far from 'taking it easy' on world cruises, Royal Navy personnel have, for a long time, been in the thick of the action on the front line in both Afghanistan and, earlier still, in Iraq."

Mr Bush, who spent 22 years in the Royal Navy, says there is no doubt that the defence review will "cut back significantly on defence spending".

While some savings could be made by purchasing more equipment "off the shelf", he stresses that the Navy still needs to train effectively at sea – not alongside in port.

If the Government is "serious about maintaining a national defence industry", it has to plan ahead and order sufficient replacement ships.

"The industrial infrastructure will rapidly diminish, indeed in some cases has disappeared, if a constant stream of orders are not forthcoming," he says.

"Specialist industries such as submarine and shipbuilding cannot survive without work. It is essential that the shipyards remain busy if the Royal Navy is to survive.

"Now is the time to be looking to order the replacements for the Type 22 and Type 23 frigates.

"Now is the time to be ordering the replacements for the mine countermeasures forces. Now is the time to be ordering the tanker replacements."

He concludes: "In the past decade, the Royal Navy has been significantly changed from its Cold War persona. But it is still relevant today – we are, and always will be, an island nation.

"It is likely that the next decade will see further change. We can only hope that it is driven by operational need rather than a Treasury who don't want to pay the insurance premiums necessary to ensure this nation's defence – not only in today's war but for the threats we are likely to face not only next year, but five years from now or 10 years from now. Defence cannot and must not be seen as a luxury."

The review, which has been published annually for more than 30 years, costs £8.99 and is available in bookshops or from www.navybooks.com