Major Joyce opens his 'golf bag' of weapons in joint exercise by the army, navy and air force

London Olympic preparations: missile launchers in Blackheath Link to this video

The language was so stiflingly reassuring, it sounded as if Londoners can sleep soundly in their beds knowing that they are being defended by the contents of a really well equipped sports locker.

"Think of this as just one club in a golf bag," Major David Joyce said, of the three stumpy green trailers parked in a large, muddy patch of Blackheath.

As well as a major joint exercise this week by the army, navy and air force to test preparations to defend the London Olympics against a terrorist attack, the services are mounting an attempt to persuade Londoners that seeing ground to air missile launchers on a roof or in the park is just another everyday occurrence, nothing to worry about at all. London will hardly notice they're there. They'll be no trouble, and they'll be gone in no time.

The first line of defence is a ring of observers around London, watching the skies through binoculars. If they detect a suspect aircraft, the next line of defence is to send up a helicopter to ask them nicely to go away. Again, surprisingly, literally. Air Vice Marshal Stuart Atha said the helicopter will be armed with a large board telling the intruder "in plain English" they are in unauthorised air space.

Major Joyce's golf bag choice includes Rapier. If its two radar units saw something appalling, he could then swap his mashie for a niblick, and fire a 42kg missile up to five miles, at twice the speed of sound. "If it misses its target it is designed to self destruct in mid-air," he said comfortingly, "don't ask me into how many pieces."

If things go beyond the capacity of the golf bag, Colonel Jon Campbell has another bit of kit: "We like to call it the goalkeeper." This the Starstreak missile, the one causing such consternation to Londoners who recently discovered their rooftops might become part of the GBAD (ground based air defence: the parts of the Olympics not secured by the golf bag will be protected by an impenetrable blanket of acronyms).

What would it sound like, and what would the fallout be, if a Starstreak was fired from the Bow Quarter flats? "I can't talk about that," the bombardier who would have to pull the trigger said firmly.

Blackheath isn't best pleased either. "Reminds me of the Duke of Wellington: "I don't know what effect these men will have upon the enemy, but by God, they frighten me," Michelle O Brien commented in the Blackheath Bugle site.

The government has not yet taken the decision to deploy either Rapier or Starstreak. "We are making prudent precautionary preparations for what might develop," Atha said. "There is no specific threat as we stand. Our hope is that anyone contemplating a malign attempt, when they see the capabilities we are developing, they would be deterred."