Hogan Lovells litigation partner Christopher Grierson has been dismissed from the firm after wrongly claiming more than £1m in expenses.

Grierson, who is best known for working on the high-profile BCCI litigation battle with the Bank of England, was dismissed last Wednesday (11 May) following an internal investigation led by the transatlantic firm's finance team.

The investigation, which started at the beginning of this year, found evidence of more than £1m in false expenses claims made in just over four years running up to the end of December 2010.

Grierson, who has co-operated fully with Hogan Lovells' investigation, will now repay the money in full within 14 days.

He also faces investigation by the Solicitors Regulation Authority (SRA) after Hogan Lovells reported the case to the regulator on Friday (13 May). No clients have been affected by the false expenses claims.

Partners were told about the fraud and Grierson's dismissal over the weekend. The firm will look at its internal control procedures in light of the investigation into Grierson.

A spokesperson for Hogan Lovells said: "An investigation carried out by the firm has revealed that no clients were affected as a result of Christopher's actions.

"Christopher acted entirely on his own. He was a longstanding partner in the firm and highly-regarded. We are very saddened and concerned by these events, which represent a major breach of trust.

"We are very clear as to our professional responsibilities as solicitors and we have promptly taken the appropriate action."

Grierson, who formerly sat on Lovells' partnership council, also advised the Financial Services Authority on the administration of Lehman Brothers.

An SRA spokesperson said: "Hogan Lovells acted promptly in reporting the matter to the SRA. We have launched an investigation and the firm is co-operating fully."

The regulator will present the findings of its investigation – which is likely to take several months – to the Solicitors Disciplinary Tribunal, which will then decide on its response, which could include a financial penalty or disbarment from the profession.