Mickie Most worked with Nancy Sinatra in 1969

Most, who had more number one hits than any other producer world-wide, died of mesothelioma, a cancer commonly associated with asbestos.

That led to speculation that the substance had been used in soundproofing tiles, which Most was exposed to.

But recording studio experts said asbestos did not have acoustic properties and was unlikely to have been used.

Neil Grant of acoustic and design consultants Harris Grant said asbestos was inefficient for soundproofing and was more commonly used for heat insulation.

"The material is extremely poor for anything we might ever want within a recording environment," he said.

"It's certainly not an efficient or state of the art material."

However, it may have been used for "sound deadening" to absorb noise in some circumstances in the 1950s and 60s, he said.

A spokeswoman for Most's record label, Rak, told BBC News Online it was "impossible" to find out the cause of Most's illness.

Lulu was among the mourners at Most's funeral

She said the producer had spent "many years in South Africa in the 50s and 60s", adding it was strange that more people in the music industry had not got the disease if studios contained dangerous materials.

"If you think of all the recording studios in the world and all the bands and producers who have worked in them over the years, and then they suddenly come up with this theory, it doesn't really make any sense," she said.

Cancer Research UK said 90% of cases of mesothelioma were caused by exposure to asbestos.

"It's impossible to say what the rest of the causes are," a spokesman said.

Friends and family

Singers and musicians paid tribute at Most's funeral at Golders Green crematorium in north London on Monday.

Famous names including Lulu, Donovan and Chrissie Hynde joined Most's wife Christina, daughters Nathalie and Crystalle and son Calvin for the service.

Most, whose real name was Michael Peter Hayes, died of cancer at home in Totteridge, north London on 30 May.

Some of the hits he produced were played at the ceremony, including House of the Rising Sun by The Animals and I'm Into Something Good by Herman's Hermits.