The existence of homicidal gas chambers at Auschwitz was completely fictitious, historian David Irving has told London's High Court.

Mr Irving, 62, who is seeking libel damages for being branded a "Holocaust denier", said eyewitness evidence of the chambers was "totally demolished" because there were no holes in the roof to insert poison.

The historian said his theory - based on research by revisionist historians - "blows holes in the whole gas chamber story".

Mr Irving is suing over Prof Deborah Lipstadt and Penguin Books over the 1994 book, Denying The Holocaust: The Growing Assault On Truth And Memory, which he says has generated "waves of hatred" against him.

His claims about the non-existence of Auschwitz gas chambers were made as he cross-examined Professor Robert van Pelt, who said there was a "massive amount of evidence" of the camp's use for mass extermination.

Giving evidence for the author and publishers Prof van Pelt said that the gas chambers were first dismantled and then dynamited when the gassings stopped in November 1944 as the Russians advanced.

But Mr Irving said a number of "revisionist" researchers had entered the ruins of Crematorium Two at Auschwitz, where Holocaust historians say 500,000 died, and photographed the collapsed underside of the roof - but found no holes.

He says the gas chambers were used only to de-louse corpses and objects.

"I do not accept that the Nazis in the last frantic days of the camp, when they were in a blue funk, would have gone around with buckets of cement filling the holes that they were going to dynamite," he told the court.

Photographic evidence

Professor van Pelt says the evidence for gassing included eye-witness accounts, photos and drawings from memory of a sonderkommando - a Jewish inmate selected to work in the crematoria.

But Mr Irving said an SS photograph, which the professor says shows four introduction columns for Zyklon B gas pellets, pictured drums containing sealant for building work.

Prof van Pelt also relied on an aerial photo taken by the Americans in the summer of 1944 which showed "four dots" on the roof of Crematorium Two which again were introduction devices.

Mr Irving questioned the authenticity of the photo and said that whatever the dots were, they were too big for the purpose put forward by the defence.

Prof van Pelt also cited the drawings, undertaken in 1945-46, of surviving sonderkommando David Olere, which showed openings for the introduction of the pellets into the gas chamber at Crematorium Three in Auschwitz.

But Mr Irving said Mr Olere's "prurient interest" in sketching naked women meant the drawings were intended to be marketable and were therefore unreliable.