The helicopter crash in the Irish Sea was the latest in a catalogue of incidents involving offshore workers in UK waters. Neil Hunter looks at the history of one of the world's most dangerous jobs.

SINCE 1969 there have been more than 30 incidents involving oil rig support helicopters, killing more than 100 people.

Britain's worst helicopter crash happened in November 1986, when 45 men died when a Chinook, operated by British International Helicopters, plunged 500ft into the sea as it approached Sumburgh airport, Shetland, on a flight from a North Sea oilfield.

Eleven men were killed in February 1992 when a Super Puma helicopter, taking oil workers from Shell's Cormorant Alpha platform 100 miles north-east of Shetland to the Safe Supporter "flotel"

200 yards away, crashed into the sea immediately after take-off.

Witnesses reported that within 15 seconds of it climbing into the air, in a snowstorm, it started a progressive descent and crashed two minutes later.

The aircraft had ditched so quickly in a 50-knot wind that the two crew members had no time to put out a Mayday message.

Nineteen oil rig workers and two crew members were rescued in July 1988 after an Sikorsky S61 helicopter caught fire and was forced to ditch in the sea.

The pilot came down 15 miles east of Shetland and the aircraft - en route from a drilling rig 70 miles off north east Scotland - sank in 200ft of water in 30 minutes.

The Sikorsky S61 was involved in another crash in July 1990 when six men were killed.

The helicopter hit a crane as it was about to land on the pad of an oil loading depot situated about 100 miles northeast of the Shetland Isles.

Two Teesside men were among 11 killed when a Sikorsky S76A plunged into the sea off Norfolk during what was supposed to be a routine ten-minute shuttle flight in 1992.

Devoted family man Douglas Learwood, 40, and 45- year-old draughtsman Stuart Coggan - who lived just a mile apart in suburbs of Middlesbrough - died along with Captain Mark Wake, 42, from York.

The main rotor blade of the helicopter - which had been struck by lightning three years earlier and was showing signs of fatigue - fractured, and caused it to plummet into the North Sea.

In August 2001, 13 men died when a twin-engined Wessex helicopter plunged into the North Sea off the Norfolk coast.

A year earlier, five men had to be rescued after a Royal Navy Merlin helicopter ditched in the Inner Sound between Applecross in Western Ross and the island of Raasay, near Skye.

Three men were killed in August 1991 when their Bell 212 crashed while on maintenance work at a platform in the Ekofisk field, in the Norwegian sector of the North Sea.

A British Airways Chinook ditched 125 miles north of Shetland following engine trouble in May 1984. All 44 oil workers and three crew members were rescued.

In August 1981, two crashes in 24 hours left 14 men dead.

In the first, a Bell 212 crashed on its way back from the Dunlin oil platform, north-east of Shetland, killing one man.

The following day, 13 died when a Wessex helicopter, chartered from Bristow, crashed into the sea 12 miles off the coast of Norfolk. It had been returning maintenance workers to Bacton heliport.

Eighteen oil men cheated death when a bolt of lightning sent their helicopter crashing into the North Sea as they travelled from Aberdeen to the Brae Field, 150 miles off the Scottish coast, in 1995.

They were rescued unhurt.

Twelve people were killed when a helicopter ditched into the North Sea while flying to a Norwegian oil rig in 1997.

On July 6, 1988, 167 lives were lost in explosions on the Piper Alpha platform, in the North Sea.

It was the worst offshore oil accident in history, and it quickly revolutionised the offshore oil industry.

The rig - about 100 miles south-east of the Orkneys - had passed a safety inspection only eight days before the tragedy, which is believed to have been triggered by a leak from gas compressors, or from the oil and gas separation unit.