LONDON - Britain is determined to tackle the problem of illicit money flows, a spokesman for Prime Minister Theresa May said on Monday, after a report by lawmakers said Russian money laundered by British financial institutions harms national security.

"The UK has taken a leading role in the global fight against illicit finance, and criminals should be in no doubt that we will come for them, their assets and their money," he told reporters.

"We are determined to drive dirty money and the money launderers out of the UK and we will use all the powers we have ... to clamp down on those who threaten our security," he said adding that since the Proceeds of Crime Act was introduced 2.2 billion pounds ($2.95 billion) has been taken off criminals.

($1 = 0.7459 pounds)

(Reporting By Elizabeth Piper. Editing by Andrew MacAskill) ((Andrew.MacAskill@thomsonreuters.com; +442075421726; Reuters Messaging: andrew.macaskill@thomsonreuters.com))