The accident in the "Dennis Shaft" of Gresford Colliery occurred at 0200 when the miners were on their mid-shift break.

A team of six men were able to escape, but all other miners working in the Dennis section are thought to have perished in the explosion or have been trapped by the fierce fire which followed the blast.

Three members of a rescue team were also killed in early attempts to reach the mineworkers who may have survived the accident.

Around 400 men were on shift in the United Westminster and Wrexham Collieries pit at the time of the blast, but those working in other sectors of the mine were able to reach the surface safely.

Emergency teams arrived on the scene shortly after the accident was reported. Local hospitals have cleared their wards and fire teams have come from as far afield as Sheffield, 90 miles (145 km) away.

Rescue-workers say conditions in the mine are extremely dangerous because of the fire in the main air intake, known as 29's Turn.

It is not yet known what caused the explosion.

It is thought this could be the worst disaster in a British mine since the accident at Senghenydd Colliery in Glamorgan in 1913, which left 439 dead.

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