Bradford's banks and businesses are on alert for crooks trying to launder stolen money from Britain's biggest robbery.

Experts have warned that the gang responsible for the theft of at least £25 million from the Securitas depot in Tonbridge, Kent, will be starting to try to spend the money and could target businesses and financial institutions based in Bradford.

The thieves are rumoured to have stolen more than £25 million and possibly as much as £40 million in new and used notes.

The money would stack up to 40 storeys high and weigh almost half a tonne.

A spokesman for the Bradford & Bingley bank said: "We have already got strict money-laundering systems in place and with all the publicity that the robbery has attracted branch staff are more than aware of keeping an eye out for unusual transactions."

Fraud expert Liesel Annible, a committee member with the West Yorkshire Society of Chartered Accountants, said: "Bradford's businesses need to be on the lookout for people wanting to dispose of large amounts of cash. The gang responsible have a very difficult job.

"They will be looking at ways of making the first step into the financial chain."

Miss Annible, who specialises in money laundering compliance and financial investigations, said: "Obvious targets are bureaux de change, luxury car dealers, builders' merchants, travel agents and unregistered money transfer companies."

Tim Brooke, Head of Group Risk at the Yorkshire Building Society, said its staff were on the alert for irregular transactions.

"We have several systems in place to prevent the criminal fraternity from benefiting from their ill-gotten gains through the society," said Mr Brooke. "We would alert the public in Bradford to be alert to large or unusual cash activities."

Naz Khan, director of sales at Project Kahn in Canal Road, Bradford, said new Acts were helping to regulate the industry.

"We have noticed a real change since the new laws were introduced and it's much better for us now," he said.

"Now we are required to ask for a lot more identification from customers if we are accepting more than £9,000 in cash."