The Metropolitan Police confirmed on Tuesday (7 January) it was making enquiries.

"On Thursday, 2 January, the Met’s Cyber Crime Team was contacted with regards to a reported ransomware attack involving a foreign currency exchange," said the Met in a statement. "Enquiries into the circumstances are ongoing."

Travelex took down its websites following the cyber attack on New Year’s Eve (31 December).

The company said it powered down its systems as a precaution to prevent a "software virus" from spreading.

An initial investigation "showed no indication any personal or customer data had been compromised" said Travelex, adding the company had drafted in a team of external cybersecurity experts to "isolate the virus and restore affected systems".

However, Computer Weekly reported on Monday (6 January) the perpetrators are demanding payment to decrypt a number of key computer files.

The attackers left instructions on affected systems detailing how the ransom should be paid in cryptocurrency bitcoin via a Chinese registered website.

Travelex is working with police and coordinating the recovery operation from its UK offices, the BBC reports.

Its various websites continue to display a message stating its online foreign currency purchasing services are unavailable due to "planned maintenance".