London, England: New CCTV images have been released showing what police believe was an aborted bid to pull off Britain's biggest jewel heist two days before it was carried out.

The Metropolitan Police on Saturday released the security camera images of the suspects outside Graff Diamonds in London's Bond Street captured two days before the Aug 6 robbery.

Detective Chief Inspector Pam Mace said police believe it was 'more than just a practice run, and that they were planning on committing the robbery on Aug 4'.

Police said they do not know why the heist was postponed, according to The Associated Press.

Two well-dressed men walked into the store on Aug 6 armed with handguns and stole dozens of rings, bracelets, necklaces and watches with a retail value of £40 million ($95 million).

A £1 million reward has been offered for their capture. Experts believe that the diamonds from the heist would make their way to Hong Kong fairs, where jewellery buyers with 'plenty of money' adopt the 'not too many questions asked' attitude.

Mr Harry Levy, vice-president of the London Diamond Bourse, told The Guardian that it will be in China where someone could wear the jewellery without it being recognised.

Attempts would also be made to break up the 43 dazzling necklaces, earrings and bracelets, and launder individual stones, of which there are 1,437.

This article was first published in The Straits Times.