Arriving at his Knightsbridge store to unveil his shrine to the couple on the first anniversary of their death in a Paris, Mr al-Fayed repeated his view that a conspiracy was likely to be behind the car crash.

Gesturing to the crowds of people by the memorial, Mr al-Fayed said: "These are the most important things for me because they are ordinary people who give me support.

"They know exactly what's happened. They will not accept the establishment or people being black-balled.

"The establishment will not accept that Dodi as an Egyptian and as my son would have been the man that would have married Diana."

Talking about the ongoing investigation into the crash, Mr al-Fayed said: "I am just looking to God. I will not rest. If it is not an accident and if it is murder, be sure that whoever did this murder will not escape from God.

"If they believe they are more powerful than God then people will come after them.

"My Egyptian curse will not let them get away with it."

He added: "Either I am wrong or they are wrong - nobody knows."

Books of condolence signed

Hundreds of people queued throughout the day to sign five books of condolence placed both outside the store and by the permanent shrine.

The shrine is 8ft high and made of bronze

Two framed photographs of Dodi and Diana have been mounted above a pool of water and surrounded by gilt birds, symbolising the couple's last Mediterranean holiday together.

"There is a lot of feeling here and so much support from so many people," Mr al-Fayed said.

"It has been a horrendous day. I have spent the morning with the family at the Dodi mausoleum.

"I just came here because of thousands of people were waiting for me. It is nice to share that."

He also refrained from sending any message of condolence to the Royal Family.

He said: "I am not sure of that really, but I feel sorry for the princes.

"I know they are very close and very loving. That is the most important thing for me - the two princes.

"The two children to have their mother is so important. But I am suffering too. I lost my son."

Friend denounces 'conspiracy'

Mr al-Fayed's allegations followed a plea from a close friend of Diana for people to stop the "grotesque" conspiracy theories surrounding her death.

Rosa Monckton told BBC Radio 4's Today programme: "There was a drunk driver, and they were speeding, and that is what happened and that is that, and I think to exploit the circumstances in the way that has been done is absolutely appalling."

She added: "I think because her death was so tragic and so banal - drunk driving - that the public and the press find it difficult to accept that such an extraordinary life could end in such a way, without some big reason.

"I think that has fuelled a lot of the comment in the last year."