HMRC investigators arrested seven men and searched nine business and residential properties along with four vehicles.

The cash, which was piled up at the currency exchange office, included Scottish bank notes and more than $30,000 in cash.

It was seized under the Proceeds of Crime Act, along with gold, electronic devices and paper records. A further £120,000 was discovered during a search of one of the vehicles.

More than 100 HMRC officers took part in the arrest operation on 9 October, which is part of a criminal investigation into alleged money laundering.

The seven men were arrested on suspicion of offences under sections 327, 328 and 329 of the Proceeds of Crime Act (2002) and have been released under investigation.

HMRC has been given six months to hold the money during the investigation.

Under the Money Laundering Regulations, money service businesses (MSBs) are defined as a businesses which ‘operates a currency exchange office, transmits money by any means or cashes cheques payable to customers’.

Margaret Mousley, deputy director in HMRC’s fraud investigation service, said: ‘We will always be on the side of the law-abiding majority and will investigate any business suspected of laundering the proceeds of crime. This is a significant amount of money and the courts have agreed we can hold it for six months whilst our investigations continue.

‘We urge anyone with information about money laundering or any type of tax fraud to report it to HMRC on gov.uk.’