Britain’s financial watchdog has launched a full investigation into Tesco after the troubled supermarket massively overestimated its half year profits forecast by STG250 million ($A456.33 million).

“The Financial Conduct Authority has notified Tesco that it has commenced a full investigation following the overstatement of expected profit for the half year,” the FCA said in a statement.

Tesco has already ordered an independent review by Deloitte and said it would “continue to cooperate fully with the FCA and other relevant authorities considering this matter”.

Last week, the UK accountancy regulator, the Financial Reporting Council (FRC), said it was “monitoring the situation closely,” but would not act until Tesco’s own investigation was completed.

The FRC can issue fines for misconduct.

It can also, via an independent panel, suspend individuals and firms from the professional accounting body.

AFP