WASHINGTON, April 6: Intelligence agents in the UK and US have foiled an alleged chemical bomb plot in Britain, the BBC said in a report on Tuesday.

The plot was believed to involve detonating a combination of explosive and a chemical called osmium tetroxide, not known as a chemical weapon agent. Experts say in gas form it could be lethal in a confined space.

The plotters were thought to be sympathetic to the aims of Al Qaeda and the intended target was believed to be British civilians, probably in London. The chemical has a legitimate scientific use for research but is highly destructive to peoples' eyes, lungs and skin.

The plot was foiled after US and UK agencies intercepted communications between the plotters and it is not thought that they had managed to obtain any of the chemical, osmium tetroxide.