Only a tiny number of law firms will be affected by a requirement to record telephone instructions from March, an expert has advised.

Ian Muirhead, managing director of Solicitors Independent Financial Advice, said the new rule is aimed at curbing insider dealing and will affect around 20 of 8,900 law firms in England and Wales. The requirement affects firms which advise on or arrange listed securities on an execution-only basis.

Firms which do not own re­cording equipment should avoid discussing securities by phone.