US lawyers are braced for further federal scrutiny of their ethical standards after the US Senate demanded a government investigation into the role of law firms in tax evasion – just days before a key report into Enron’s collapse criticised the company’s legal advisers.

The Senate subcommittee report, issued on 20 November, called for the US Department of Justice and the Internal Revenue Service (IRS) to jointly investigate tax shelter activities at US law firms following a year-long investigation.