In January, Shell admitted that it had overstated its oil reserves by a fifth.

If found guilty of market abuse, Shell would face potentially huge fines.

It comes on top of the news that the US regulator, the Securities and Exchange Commission, has also launched its own separate investigation into whether or not there was any breach of market rules on the part of Shell.

Former chairman Sir Phillip Watt resigned over the reserves furore.

A working group appointed by Shell's audit committee has undertaken a probe of the overstated oil reserves and is due to report publicly on this in the next few weeks.