Filmed confessions were later retracted by two of the men

The six men were granted "royal clemency" and flew into London from Saudi Arabia on Friday afternoon, having spent more than two years in prison.

They had been convicted of a series of bombings in 2000 and 2001 that left one Briton dead and several Westerners injured.

They had all maintained their innocence despite two of them confessing on film to the blasts. The confessions were later retracted.

Saudi Arabia claimed the men were involved in a turf war over bootleg alcohol, while the men's supporters said the authorities were ignoring the possibility that Islamic militants could be responsible.

Reluctance

The head of the Middle East and North Africa programme at the Royal United Services Institute, Daniel Neep, said terror events - internally and externally - have prompted Saudi Arabia to reassess its stance.

"The Saudis were reluctant to acknowledge the problems they had a home until relatively recently.

"This began to change after 9/11 and began to change even more recently after the May bombings in Riyadh."

Thirty-five people, including nine suicide bombers, were killed in three explosions in the capital city in May. The attacks were centred on ex-patriate residential compounds and were linked to al Qaeda.

"The Saudis now are fully aware of the fact that they do have a problem with terrorism at home, with Islamic fundamentalists, and they have introduced a significant number of steps to clamp down on these militants," Mr Neep told BBC News 24.

"It is a problem they are actively dealing with and why much of the criticism, coming from the US in particular, they think is unfounded."