It is understood the bank called in police to its Canary Wharf headquarters on London on 25 April after detecting suspicious activity within its securities services division.

The bank and police have declined to give full details of the incident. However, press reports state that HSBC's main euro account was cleaned out before the bank traced a single EUR90 million transaction moved from the account. The bank is understood to have recovered the missing funds.

In a statement, the bank says: "HSBC is cooperating fully with a police investigation into an alleged fraud at the bank. As the matter is before the courts we cannot comment further. No customer funds were involved and no transactions were disrupted. No customer or bank funds were lost in the alleged fraud."

A spokeswoman for City of London police confirmed Jagmeet Channa, 25, of Ilford, was charged with conspiracy to defraud, money laundering and abusing a position of trust.

Channa has been remanded in custody until June 25, when he will appear at Southwark Crown Court. Three other men aged 26, 33 and 38 remain on police bail in connection with the investigation.

However it has not been confirmed that Channa or the others worked at the bank. The alleged fraud is thought to have involved trade settlement staff at the securities services division, which provides custody services to third party accounts.

The HSBC news comes with banks still under the spotlight over risk and security. In March the Financial Services Authority called on City banks to tighten up systems and controls in order to prevent a repeat of the rogue trading scandal at French bank Société Générale.

SocGen shocked the banking world in January when it reported a massive EUR4.9 billion in losses allegedly perpetrated by junior trader Jérome Kerviel who used loopholes in controls and risk management procedures to conceal fictitious transactions.