This boy was captured on CCTV as he jumped Enlarge Image

Milford Haven Port Authority is not allowing children to play or swim in the area following the incident.

Two youngsters were seen to jump from the ship, but got away before the authorities arrived.

The ban follows a spate of incidents recently involving children which has concerned the port's authorities.

In one case, children narrowly escaped being hit after jumping into a lock into the path of a boat.

Myra Shacklady, commercial director at the port authority said one of the reasons children were now banned from the harbour was for their own health and safety.

"They were jumping from a greased pole into less than six feet of water.

"It's been after a long period of consultation with the local community police and in actually monitoring the situation and warning [the youngsters] and trying to educate them into being more responsible."

Ms Shacklady said there was one particular area near Hakin Point in the harbour where children could go to swim, but the authority had now stopped access from their land.