Police have recovered more than £20 million from the £53 million raid on the Securitas depot in February but they believe millions more are still hidden in the South-East.

Senior detectives think the raiders mounted a meticulously planned operation but they may have been panicked by the huge wave of publicity after the raid.

They may also have miscalculated the ease with which the cash could be laundered. Instead millions of pounds have been split into smaller amounts and stuffed into bags. Some could then have been buried or hidden in lock-up garages, safe deposit boxes and homes.

Investigators think other cash has already been spent possibly on property and a team of ten financial investigators is being formed to chase money trails.

New legislation aimed at money launderers has made it more difficult to spend or invest large amounts of cash without declaring a legitimate source but cash purchases could be easier abroad.

Kent officers have now charged nine suspects accused taking part in the raid or other involvement. In the last few days they have arrested two more men and two women on suspicion of plotting the robbery, kidnap or assisting offenders.

In all police suspect 40 or more people may have been involved in the robbery, helping to prepare and plan it or money laundering afterwards.

Seven raiders attacked the depot after kidnapping the manager and his family but the robbery took eight months to prepare.

Yesterday Mike Fuller, the chief constable of Kent, issuing a new appeal for help in finding the missing cash, said the cash seized so far had been found in 13 different seizures. They are now waiting to discover if £1 million found last week is also part of the Tonbridge haul.

He said: "We are very confident there is a substantial amount hidden in South East. We are very keen to find out where that is hidden."

Announcing rewards which could total £1.5 million or five per cent of the value of the missing cash and the re-opening of a hotline Mr Fuller said: "I’m confident there are people who are very close to the people involved who may now feel that they are able to come forward to give us information."

Mr Fuller said he believed they had got the "principals", but said police would continue to work to identify those on the periphery.

He said: "A lot of support was needed to get vehicles and all sorts of other things. There were a large number of people on the periphery in the planning and preparation."

The chief constable praised the "dedicated and determined" team of 60 officers which has been working "tirelessly" on the inquiry. So far, 9,724 exhibits and 2,183 statements have been taken and 235 suspects have been interviewed. A total of 36 people have been arrested.

On Sunday Lee "Lightning" Murray, a 26-year-old martial arts champion, was arrested in Rabat, Morocco, by armed officers on suspicion of robbery, kidnap and other offences linked to the raid.

Mr Fuller said Mr Murray, who is half Moroocan and comes from Sidcup, south London, had been held after a "substantial period of surveillance" and his arrest was "highly significant".

Police say it may take months to extradite Mr Murray and Moroccan officers are coming to Britain for a briefing on the case. If the delays are very long it may be possible to send a deposition to Morocco for the trial to be conducted over there.

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