Britain understands the threat posed by submarines to both trade routes and naval assets. Several times during the Second World War (and indeed once or twice in the Great War) the Germans came close to strangling our sea-borne supplies causing Churchill to observe: ‘The only thing that really frightened me during the war was the U-boat peril.’

Whilst the Chinese are not exactly about to start sinking shipping in the Western Approaches, it is engaged in building a blue-water fleet based on aircraft carriers and submarines. It is right to wonder what it has in mind doing with such a fleet and how the West ought to react to it.

This report in the Daily Mail reminds us that Chinese technology has made considerable advances, some of which have come as a nasty shock to the West. What is so worrying is that this is not the first time such an incident has happened, for on 26th. October 2006 a submerged Song S20 class attack submarine shadowed Japan-based USS Kitty Hawk in the East China Sea near Okinawa without detection. The boat then surfaced less than five miles from the carrier and only then was it spotted, by one of the carrier’s planes on a routine surveillance flight.

The submarine is normally equipped with wake-homing torpedos and anti-ship cruise missiles (ASCMs). Disclosure of the submarine encounter came while Admiral Gary Roughead, Commander of the US Pacific Fleet, was actually in China holding talks with Chinese navy leaders. It was a considerable embarrassment to Admiral William J. Fallon, Commander of US forces in the Pacific, who has initiated an ambitious military exchange programme with the Chinese.

The Song Class were China’s first new-design, conventionally powered submarine and represent a blend of Chinese and Western technology. Their design has several key features that point to a major shift in diesel submarine design philosophy. It is the first Chinese submarine to have a skewed propeller. The Song also is the first Chinese submarine designed to carry the developmental YJ-82, China’s first encapsulated ASCM capable of launching from a submerged submarine. Songs are probably fitted with flank-array sonars of French design, which will hardly cheer up enthusiasts of a rapprochement with President Sarkozy. Chinese diesel submarines are fitted with German MTU diesel engines which in turn will hardly cheer anyone who wants to cosy up to Frau Merkel.

Overall, their shape is like that of Western submarines and their technology is equivalent to the international level of the early 1980s. Incorporating a German propulsion system and advanced hydrodynamic design, the Song-class is said to be as quiet as the American Los Angles nuclear submarines. But its overall performance is constrained by the use of 1980s technology. They are said to be a less than satisfactory design. Problems reportedly include excessive noise radiation which makes the appearance of the submarine in the middle of the task force all the more worrying.

Intended to replace the aging Ming-class submarines, the first Song-class submarine was launched on 25 May 1994 and started sea trials in August 1995. but did not become operational until 1998, so they are not exactly brand new, out-of-the-box, bits of kit.

That a submarine of a potential enemy should have the ability to sneak past the guard of the world’s biggest and supposedly best navy will have made numerous Admirals have serious heart palpitations. The implications of the incident are chilling. It must be assumed that The Chinese submarine was at some stage in a position to fire torpedoes or other armaments at the USS Kitty Hawk, an 84000, steam-turbine driven aircraft carrier that is now the oldest on the US Navy inventory. As the Flagship of a carrier task group she was surrounded by vessels that are supposed to protect carriers from just this sort of possibility.

One would have liked to have been a fly on the wall at various discussions between the force commander and the various captains of the ships that were supposed to pick this intruder up: one imagines that ‘animated’ is the mildest way in which one might describe those interchanges.

I observed yesterday that this is a perfect moment for us to consider, in the light of the current events and the way matters have actually played out since the ending of the Cold War (as opposed to how we thought they would play out), what our defence needs should be for the second quarter of the 21st. Century.

One of the big factors we have to consider as a trading nation dependent on oil and other resources is how we are going to protect our interests that may be threatened by an expansionist and imperialist China that wields the major power that a blue water navy brings. At the moment we would be quite incapable of taking part in a war against a major, conventionally armed foe. Quite apart from the major repairs we need to make to all our armed forces, it is the future threats of China and Russia that ought to be occupying our attention as much as the light wars in Iraq and Afghanistan which are conflicts of a quite different stripe.

With Russia also showing signs of rearmament, backed by lashings of petrodollars, it is pertinent to ask whether our conversion of significant parts of our military into a glorified paramilitary gendarmerie is such a brilliant idea after all. Some may respond that we should be planning now to meet the conventional threats that lie ahead and be planning now to restore our armed forces to a degree of equipment and fighting efficiency to take on such threats.

This will cost money, lots of money, which will have wastrel politicians throw their hands up in horror at the implication that they will have less to waste on their pet projects. Others may be disposed to take the longer view: our freedom and ability to trade with the world are things upon which no price may be set.

But, if push comes to shove, I, for one, am quite willing to dispense with any number of Gender Awareness Officers.

In the meantime the Independent reports today that Lord Guthrie, who has been out and about all week banging the drum for the military, came close to resigning as Chief of the Defence Staff under Blair in 1998 because our present Prime Minister as Chancellor was being so unsympathetic to the defence needs of the nation. This confirms my assertion that the present parlous state of the military is down to Brown and Brown alone, so that when he goes on about how sad he is at the death of yet another serviceman or servicewoman in Iraq or Afghanistan, one should remember that any tears are but crocodile tears.

So, a large and rather open goalmouth is opening up for the Tories: will they take it? On current form that is to be doubted. If they fail, however, theirs is a considerable dereliction of duty.