Launch Reading the ground Identifying the target Hitting the target Future technology BGM-109 Tomahawk

Smarter missiles will avoid hitting targets that have already been destroyed

According to the plans, the new Tactical Tomahawk could be re-programmed in flight to attack one of 15 pre-loaded targets.

But it could also fly around a target sending images back to base.

If the battle commanders concluded the target had already been destroyed, they would be able to redirect the missile elsewhere.

With existing versions it can take hours to change the target before the missile is fired, and once launched it is on its own.

The US Navy says the new version is expected to enter service in 2004, although it is thought some might already have been deployed.