A coroner has called for warning signs to be posted by harbour sandbanks after hearing how a boy drowned trying to reach one.

Stefan Allen, seven, was swept away by a strong current and another boy passed out after they got into difficulties in the Prinsted area of Chichester harbour in August.

A Coastguard helicopter crew found Stefan in the water but efforts to revive him failed.

An inquest at Chichester heard Stefan, of Cammel Road, Ferndown, Dorset, was staying with his mother Gay and his brothers Dominic, 14 and Drew, 11, on a yacht owned by his grandparents, moored in a marina.

Stefan, Drew and family friend Christopher Fleetham, 15, also from Ferndown, were playing when they set off down a path leading to the sandbanks.

The path turned into a channel and gradually became covered in water.

The inquest heard, because Stefan did not want to get his shoes wet Christopher gave him a piggy-back.

In an interview with police after the tragedy, Christopher described how the water was just below their knee caps "when it took a sudden dip and we fell together".

Drew swam to call for help, while Christopher struggled to keep Stefan, who started to panic, above the water.

He told police: "I tried to keep him up but I kept going under, swallowing water. I swallowed so much I couldn't breathe."

Christopher thought he must have blacked out. When he came round and found himself almost on the bank, Stefan had disappeared.

Stefan's grandfather Geoffrey Garner said there could be strong undercurrents.

He added: "It doesn't look that strong on the surface, unfortunately."

Recording a verdict of accidental death, West Sussex deputy coroner Martin Milward said the family must have been devastated.

He added: "Signs should be posted at both ends of the sandbank, warning of the dangers."