Tax officials will win new rights on Friday to intercept phone calls, e-mails and letters and to bug homes and private vehicles in a big expansion of their powers.

Revenue & Customs staff can use such techniques during criminal investigations into drugs and guns but they will now be extended “across the board” under the Serious Crime Act. The act gained royal assent last October but the relevant powers are contained in a “commencement order” that comes into effect on Friday.