It is hard to tell Jimmy Brown he's a lucky man. One

minute he's taking a leisurely walk with his dog, the

next he's blinking amid the rubble of his once beautiful

country cottage, clutching a singed Bessie and explaining

that all he did was light the gas stove.

The explosion that tore the face and roof off 70-year-old

Brown's Wiltshire cottage is thought to have been caused

by a gas leak. When Brown returned, he pressed the

ignition on the stove, which did its job admirably - just

with more gas than expected.

The fact that Brown was unharmed but for a few cuts

and bruises is remarkable. Gas explosions are as violent

as they sound and as deadly as they look. A blast at a

kebab house in Hull last year was followed by 999 calls

from seven miles away. Debris from the one that

obliterated Brown's house damaged 15 vehicles.

Explosives experts believe that one explanation for

Brown's escape is that he was almost directly at the

centre of the blast. As gas explodes, it produces a

powerful shockwave that surges away from the ignition

point. This blast, and the heat radiated from the

combusting gas, are the things to avoid if you want to

survive an explosion.

The effect has been witnessed by accident inspectors

brought in after industrial explosions. In 1974, an

explosion at the Nypro chemical plant in Flixborough

near Scunthorpe killed 28 workers, injured 36, and

destroyed surrounding buildings. Inspectors noticed that

away from the centre of the blast, lampposts had been

twisted and flattened. But near the centre of the

explosion, they were still standing upright. If Brown had

been further away from the centre of the explosion, it is

possible that the full brunt of the shockwave would have

"ripped his lungs out", as one expert put it.

What still baffles scientists is that Brown does not appear

to have suffered serious burns. In most gas explosions,

the heat of the blast is hard to escape, because it radiates

in all directions.