Skaters using the halfpipe opposite St Helier Hospital on Wednesday afternoon must have thought they had peformed an illegal manoeuvre when two Royal Air Force Merlin helicopters suddenly appeared overhead.

But fortunately for the dozen or so youngsters using the skatepark the RAF were only conducting a training touchdown exercise.

The helicopters carefully circled the landing area, one of the two football pitches opposite the hospital , and then touched down for a few minutes before taking off once again and heading back to their base.

Word got out that the two Merlins would be landing at approximately 2pm and in rather uncharacteristic style as they were 10 minutes late.

But onlookers who stayed to watch were treated to a controlled display of flying by the two trainee pilots.

One spectator, Ricky Anderton, said: “It was like something out of Apocalypse Now, I kept expecting some Wagner to start playing while they flew in to land.

“The kids in the skatepark looked a bit nervous when first the police arrived in front of them, then the two Merlins arrived behind them. It was hilarious.”

A spokesman confirmed the helicopters had come from RAF Benson in Oxfordshire and the pilots were completing part of their training in an exercise called an “Operational Convergence Flight”.

The Merlins were designed in 1979 and are over 22 metres in length. They can maintain a top flying speed of 280km with a range of over 1,000 miles.