The joint operation between the FCA and the National Crime Agency saw 38 officers remove digital devices and search three London residential properties.

All 3 individuals were interviewed under caution by the FCA, with 2 being released under investigation and one on unconditional bail.

A fourth suspect has been interviewed under caution and remains under investigation.

Steve Smart, joint executive director for the FCA, said: “Insider dealing poses a significant threat to the integrity of financial markets both in the UK and overseas. The FCA is committed to combatting organised criminal networks involved in this threat. 

“We work tirelessly, using our own sophisticated monitoring systems and specialist teams, to identify and disrupt people involved at each stage of these trading events from the insider leaking information, people who sell inside information to traders and brokers who facilitate access to the trading market. 

“Working with our domestic and international enforcement partners we will continue to use all the powers and tactics available to us to disrupt this threat.”

The regulator said it cannot comment further or publish further details at this time.