HM Revenue and Customs tax officials will be able to access suspects' emails and internet browsing records from today.

Amendments to the Regulation of Investigatory Powers Act 2000 (RIPA), brought in under last year's Serious Crime Act, came into force this morning.

But the new powers will not go unchecked, said an HMRC spokesman.

"All surveillance is subject to scrutiny by the Office of Surveillance Commissioners (OSC) or the Interception of Communication Commissioner's Office," he said. "We undergo annual inspections by both of these bodies."

The changes also allow tax inspectors to intercept phone calls and letters.

Customs officials already had intercept rights in their capacity to investigate cases of drugs and arms shipments.