Organisers of the Olympic Games are still in a state of shock following the three bomb explosions outside a police station that rocked Athens on Wednesday.

Though they played down the attack - which came exactly 100 days before the opening ceremony on August 13 - saying that it was not connected to the Games, they admitted privately that it was an embarrassment that could not have come at a worse time.

A source at Athoc, the Games' organising committee, said: "It is very embarrassing and the timing could not be worse, but the Games will go ahead. The Barcelona Olympics took place while ETA was in full force. Atlanta went ahead just months after the Oklahoma building blew up. These things happen." 

According to The Times, London, the cost of insurance in case the Games are called off has rocketed as a result of the pre-dawn explosions.

But officials said that there is little that they can do to prevent a repeat attack. A senior government official told The Times: "This type of attack could happen anywhere in the world - in London or New York. There is nothing we or any other city could do to stop it. We can't have police officers on every corner in Athens." 

Sponsors and television networks will now have to pay more than 30 per cent more to protect their investment in the Olympics.

Francis Fernandes, partner at London actuaries Lane Clark & Peacock said: "Insurers will be more nervous about taking on such risks based on rates before the bombs. Even if they aren't linked to the Olympics, premium reviews are likely to move prices in only one direction - up."

The blasts caused no injuries, but damaged the police station and destroyed cars.  The homemade devices - comprising sticks of dynamite rigged with alarm clocks - exploded within a half-hour span in the densely populated suburb of Kallithea, which is not near any key Olympic sites.

The International Olympic Committee is due to begin its final review of Athens' troubled preparations on Monday.