Marks & Spencer shareholders are again being urged to vote against chief executive Sir Stuart Rose’s promotion to chairman at next month’s AGM.

Corporate governance research group Pirc has advised opposition to oppose Rose’s election to the dual role.

Pirc said to investors: “Combining the two roles in one person represents a dangerous concentration of power that is potentially detrimental to board balance, effective debate and board appraisal.”

The Association of British Insurers (ABI) has also advised its members to object.

According to reports, the ABI has issued an “amber top” alert drawing its members attention to what it considers to be breaches of corporate governance in resolutions acquiring shareholder approval.