By Jeremy Olver

Stories regarding the decline in the size of the Royal Navy have become a newspaper favourite (the latest being yesterday's Sunday Times); a topic that can be counted upon to stir debate in the letters page of the Daily Telegraph. Yet an actual analysis of the Royal Navy's core fighting capabilities tells a very different story.

In the post Cold War era, these have been focused in three particular areas: naval air power; amphibious warfare; and nuclear powered submarines. Each of these areas has undergone - or is currently receiving - massive investment. Furthermore, key decisions have been taken that will guarantee their strength for years to come.

The decision to renew the submarine based nuclear deterrent confirms the Senior Service's continued role as the ultimate guarantor of Britain's defence. By extension, the requirement for to maintain the skills necessary to build a new generation of SSBNs assures the current construction programme for the Navy's fleet of non nuclear armed SSNs.

Meanwhile, the revival of the amphibious capabilities can be traced back to the arrival of helicopter carrier Ocean in 1998. This was soon followed by the long overdue replacement of veteran assault ships Fearless and Intrepid. The final stage was the replacement of Royal Fleet Auxiliary's landing ships with much larger vessels.

The order has finally been placed for two new aircraft carriers (CVF). It is difficult to overstate the ramifications (not to mention the historical ironies) of this decision. In short, the Navy is back – big time.

With the first steel scheduled to be cut imminently, you may think the Royal Navy can perhaps allow itself to breathe a sigh of relief. However, you would be wrong. Whilst the Navy's core fighting capabilities are secure, legitimate questions remain about the size and composition of its frigate and destroyer fleet.

Perhaps more so than the other two services, the Navy has never solely been a war fighting force. It has existed as much for peace and security – as a sort maritime policeman - as it has for open conflict. This dual role was exemplified by the post war escort. It was designed with a primary war fighting role as a foremost concern.

For destroyers this has been to protect other ships, particularly carriers and troop ships, from air attack. Frigates, meanwhile, have largely specialised in anti-submarine warfare. However, in addition, destroyers and frigates alike have been able to fulfil many of the Navy's secondary roles. So a frigate optimised to hunt submarines in the North Atlantic might equally find itself chasing pirates in the Caribbean or paying goodwill visits to British dependencies in the South Atlantic.

At first glance, having a versatile fleet of ships able to fulfil any task required of them seems a fairly sensible state of affairs. And it worked - so long as the Royal Navy had enough of them. But anti submarine warfare and air defence require ships that are brimming with sophisticated equipment. The Royal Navy proudly boasts that its new Type 45 air defence destroyer can take out a target the size of a cricket ball traveling three times the speed of sound. Technology like that doesn't come cheap. It doesn't stay still either. Equipment requires continual replacing and updating. So the Navy has found itself building ever more expensive vessels in ever fewer numbers.

It is also in the escort fleet that the Navy has paid the highest price for its two new carriers. First there were the six Type 22 frigates sold off under the 1998 Strategic Defence Review. Then in 2003 a 'New Chapter' was added to SDR which saw three Type 42 destroyers and three Type 23 frigates disappear from the books – the latter particularly galling considering one, HMS Grafton, was less than ten years old. But at least Grafton had made it into service. The same review reduced the planned number of Type 45 destroyers from 12 to 8 – and then the seventh and eight units were cancelled.

This has and will continue to place a degree of strain on the Fleet. Some years ago, the Navy reduced the pressure by combining a number of its standing tasks. Now it is to receive only six Type 45 destroyers, it is difficult to see them being spared for any other role than that of escorting the carriers. They have become almost as valuable as the very ships they are designed to protect.

So surely the obvious solution is to fund the Navy sufficiently to build more Type 45s? Actually, the right answer is more complicated than that.

Even if the defence budget were respectably increased, it is unlikely that the Royal Navy could have enough Type 45 destroyers built to fulfil all its requirements. At £1 billion each, it would also be wrong. That cost can be justified in terms of their war fighting role. If your Navy has two 65,000 tonne carriers carrying forty aircraft and 1,500 people, then they must have the best protection that money can buy. However, it becomes less defensible in regard to other tasks. The number of Type 45 destroyers should therefore be determined by their primary role. The Government has deemed six to be necessary; some may argue for eight. Either way it is right to build sufficient number to protect the fleet for air attack – but no more.

That still leaves a shortfall between the Navy's commitments and the number of ships available for tasking. The solution lies in the fact that the opposite is true for general purpose tasks as is the case for specialist warfare. You don't need particularly complex ships but they do need to be built in larger numbers. The time has therefore come to split the primary and secondary roles and create a two tier fleet: a small number of expensive but advanced ships to undertake the primary war fighting roles, serving alongside larger numbers of simpler, cheaper vessels that can carry out the myriad of lesser tasks.

In the recent past the Royal Navy has always steered clear of this option, believing that to remain at the top of its game it must not sacrifice quantity for quality. However, it may not have a choice. Only recently it was revealed that the two eldest Type 42 air defence destroyers have been operating for months without their Sea Dart missile system and only eight of the remaining thirteen Type 23 anti submarine frigates will receive new sonar. Better the Navy take its own path to this solution than find it forced upon it as a fait accompli.

If the Navy needs further reassurance then it could do worse than look to.....dare I write this?...the French. The Marine Nationale has operated a two tier fleet for decades and as a consequence have a numerically larger fleet than the British. The U.S. Coastguard, protecting economic interests such as we have in the North Sea, and guarding their borders against smuggling of all sorts, doesn't need a blue water capability, and could be another object lesson.

When one begins to contemplate the options available, it is possible to see other benefits too. Plenty of commercial designs for ocean-going patrol vessels, corvettes and light frigates exist that could be bought off the shelf cheaply and quickly. They could even be based abroard where they are needed for extended periods of time, something that has worked very successfully with the Falkland Islands patrol vessel and with minesweepers based in the Gulf.

There is some evidence that thinking within the Ministry of Defence is moving this way. An early study for the Future Surface Combatant programme, which will replace the current frigate fleet, examined the possibility of three distinct grades of ship: one to fulfil the anti-submarine role, a second to undertake more general naval duties and a third that would essentially be an enlarged patrol vessel capable of undertaking low level duties. Although this is promising, recent naval planning is littered with designs that began life on the drawing board as a cheap and cheerful warship but left the slipway as a monstrously expensive behemoth.

The Government has reasoned that the cuts that have occurred over the past ten years are part of the rebalancing of the fleet from a Cold War force to one suited to asymmetric warfare in the post-9/11 environment. Certainly the large scale submarine threat has all but disappeared since the collapse of the Soviet Union. However, transforming the Navy is a two stage process. Letting go of those vessels that are no longer relevant is the first part, but if true rebalancing is to occur then this must be followed by the introduction of alternative vessels that are suited to the current and future strategic environment.

In other words, the Government has done the easy part, which just so happens to be financially rewarding. But if it is genuine it its claims that these decisions are policy driven, then it must see them through. The Future Surface Combatant provides the opportunity. Consequently, it is in the interests of both the Royal Navy and the Government – and not to mention the defence of the realm – to get this project right.