What if Guy Fawkes had succeeded?

Guy Fawkes would have devastated Central London if his gunpowder plot had succeeded, according to physicists.

As well as destroying the Houses of Parliament, the blast caused by 5,500lb of gunpowder going off would have wrecked Westminster Abbey.

Buildings as far away as Whitehall would have lost walls and roofs and streets within a third of a mile would have suffered damage.

To coincide with this year's Bonfire Night celebrations, scientists worked out how much damage Fawkes and his conspirators would have caused if they blew up Parliament on November 5, 1605.

The 5,500lb of gunpowder which he packed in a cellar beneath the old Westminster Hall would, if prepared properly, cause the same devastation as a similar amount of TNT today.

Geraint Thomas, of the Centre for Explosion Studies at the University of Wales in Aberystwyth, said: 'We can use the weight of explosive to work out how it will affect its surroundings. We know that the more explosive we have, the more energy will be released when the charge is set off.

'From the pressure pulse generated by the explosion, we can tell if windows are going to be smashed or if whole buildings will be demolished.

'If Guy Fawkes was an expert in explosives and knew what he was doing and had the gunpowder confined in barrels and well packed, it could have been almost as powerful as the equivalent TNT explosion, so this is a fairly good model.'

Fawkes and 12 other men conspired to blow up Parliament in an attempt to kill King James I, who was persecuting Catholics.

Fawkes was caught red-handed in the cellar with the gunpower - although some have always claimed he was framed.

He was later tried, hanged, drawn and quartered as a warning to any other would-be traitors.