A bald, naked man, who said he was a British tourist, has gone swimming in the moat of Japan's Imperial Palace.

Eyewitnesses in Tokyo said he managed to climb the palace wall, throwing rocks and splashing water at police before being taken into custody.

Television footage showed the tall man getting out of the water at one point, chasing police with a rock and a plastic construction site pole.

He then went back to the murky water and swam across to the other side of the moat, climbing up the eight-metre stone wall of the palace.

He was caught by two policemen, after a chase which eyewitnesses said lasted for an hour-and-a-half.

One witness said: "I've never heard of anyone doing such a thing. He must be a bit crazy."

Television pics showed passers-by gathering around the moat and watching the chase, giggling and taking photos on mobile phones.

Police said it was unclear what his motives were, although media said he had dropped a bag in the water.

The man, aged around 40, first said he was Spanish but later said he was a Briton living in Spain, police said.

A police spokesman said they are checking on the man's mental condition and he was later released.

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