A former fund manager at the London division of asset manager BlackRock on Wednesday pleaded guilty to insider dealing in a London court.

Mark Lyttleton was in September charged with three counts of insider dealing relating to trading in equities and a call option between October and December 2011.

A spokesman for the Financial Conduct Authority said Lyttleton had pleaded guilty to two counts. He will be sentenced at a later date.

Lyttleton worked at BlackRock Investment Management (UK) Ltd between 2001 and 2013, according to the FCA's register of financial appointments. He was arrested on suspicion of market abuse in April 2013, according to one source familiar with the investigation.

Blackrock, the world's largest asset manager, reiterated that it had been told by the FCA that the charges related to alleged actions carried out for personal gain, while off its premises. There was no impact to any of its clients, it said.

Insider dealing is a criminal offence in the UK and is punishable by a fine and up to seven years in jail.