Two men are fighting for their lives after an accident during a diving expedition.

An investigation has been launched into why the pair resurfaced too quickly.

One was hauled unconscious from the water. His dive buddy was suffering from the bends.

Coastguards received an emergency call from Ivan Warren, skipper of the Michelle Mary, at 4.19pm yesterday.

The pair were among a group of six diving on a wreck 11 miles off the coast of Lancing, when they got into trouble and resurfaced without taking enough recompression stops.

Both were airlifted ashore by helicopter and transferred by ambulance to the Queen Alexandra Hospital in Cosham, near Portsmouth.

The remaining members of the dive group, all from the North, were safely returned to the shore with assistance from coastguards and the Shoreham lifeboat.

A spokeswoman for the coastguard centre at Dover said: "We had one diver who was unconscious and one with possible bends - they are both life threatening conditions.

"For some reason or other they missed some of their recompression stops which causes the bends."

A spokeswoman at the hospital declined to give any information about the condition of the men.

Skipper Mr Warren said: "We cannot make any comment at the moment.

"We are talking to the coastguards and we do not know what caused the accident.

"One of the men must have had problems of some sort and we are trying to find out exactly what happened.

"I was on the boat at the time and called the coastguard."

The drama happened exactly a year after two men diving from the same charter boat were killed in a tragedy at sea.

Clyde Warner, 56, from Slough, and Martin Reed, in his 50s and from Uxbridge, were part of a seven-strong team exploring the wreck of the Bessel, 15 miles off Shoreham.

Mr Warner shot up too quickly and died later in hospital. Mr Reed's body remained in the sea for 24 hours before it was discovered by divers on the seabed.