Deloitte is facing questions over the level of fees it has received for non-audit work provided for one of its audit clients, FTSE 100 insurance company RSA.

RSA's latest annual report shows the company paid Deloitte £10m in 2012 for management consulting as well as tax and other advice, compared with less than £6m in auditing fees.

One leading institutional shareholder described the non-audit fees as 'surprisingly high' and said 'the numbers are unusual - people are going to focus on it.'.

Deloitte has been RSA's auditor since 2007 but is set to be replaced by KPMG, subject to shareholder approval, at the annual meeting next month.

Commenting on the change in its results statement in February, RSA said 'perception' of the independence of Deloitte as auditor could be impaired after the firm was appointed to conduct further consultancy work on RSA's technology restructuring at its Scandinavian business, following an initial engagement last year.

Investors have also raised concerns about the connections between the new auditors and Alastair Barbour, who was appointed chair of RSA's audit committee last June. Barbour retired from KPMG in March 2011 after 36 years with the firm.

In a statement, RSA said the audit committee's chairman 'has no remaining financial or other interests in his former firm. The Board is satisfied that Alastair is fully independent on this issue.'

Deloitte and KPMG have made no comment.

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