UK retailer Marks and Spencer will be sending a letter to shareholders detailing CEO Sir Stuart Rose's move to executive chairman, as disgruntled stakeholders air their criticism of the plans.

A number of M&S' institutional shareholders, including Legal & General and Schroders, are thought to be unhappy about the executive change due to concerns over corporate governance guidelines.

However, an M&S spokesperson said that the move was compliant with such guidelines, and that the majority of shareholders the company had polled were supporting the appointment.

When asked about the letter, the company spokesperson said: "Nothing has gone out yet, but it is something we've been planning to do all along."

M&S is keen to keep hold of Sir Stuart, who has been credited with turning around one of the flagships of the UK High Street.

Sir Stuart also has ambitious future plans for the business, spearheading its "Plan A" environmental project and ambitious international growth.

"We accept that it is an unusual move but think it is the right decision at the moment," the spokesperson added.

Sir Stuart will take up the new role on 1 June for a three-year term, before he retires in July 2011.

The appointment, announced last month, is part of an executive overhaul that also sees current non-executive chairman Lord Burns stand down, and Ian Dyson become group finance and operations director.