David Wragg: To delay defence spending is to invite a disaster

I find it alarming that Geard DeGroot knows so little about defence, yet is Professor of Modern History at St Andrews. He wrote in these pages last week about the "thick armour that protects a British frigate", clearly ignorant of the fact that frigates do not, and never have had, armour, but are thin-plated and vulnerable.

He also seems to think that nuclear powers are friends. China is no one's friend, and post-Soviet Russia has behaved as pre-Soviet Russia - as a difficult neighbour and bully, albeit using the "energy weapon" rather than force of arms. Are nuclear-armed India and Pakistan friends?

It is true, of course, that the needs of our forces in Afghanistan have been neglected. It takes time to change defence priorities, but this far into the conflict, much more should have - and could have - been done.

Nevertheless, he is clearly unaware of how long defence equipment takes to procure and the changes that can occur during the operational life of that equipment. Take the infamous defence review conducted by John Nott, centred on naval aircraft. The following year, 1982, Argentina invaded the Falklands, and the lack of air power saw the loss of two destroyers, two frigates and a merchantman carrying helicopters, as well as a landing ship of Welsh Guards.

People like Mr DeGroot don't grasp that defence is expensive, but not having it is more expensive. Waiting until we can afford defence is like saying that one will pay the fire insurance when we can afford it, but the fire might come before then.

Canada and Australia are both rebuilding their armed forces. The latter has commissioned two combined helicopter carriers and assault ships larger and more capable than anything the Royal Navy has. The Royal Australian Navy also foresees doubling the number of submarines with cruise missile capability.

Yes, replacing Trident on a like-for-like basis might be over-ambitious, and I agree that the possibility of a cruise missile-based nuclear deterrent should be considered, but doing away with it altogether? No!

• David Wragg is author of The World Air Power Guide, publihsed by Pen and Sword