A leading private shareholder organisation has added to concerns expressed by institutional investors about Marks & Spencer boss Sir Stuart Rose’s proposed elevation to executive chairman.

UK Shareholders Association (UKSA) director Roger Lawson told Retail Week that Rose’s move “looked difficult to justify” and was at odds with the combined code of corporate governance.

He said UKSA was not taking an official position on the row, but added: “Our view is that we support the combined code and we’d look, therefore, to have a non-executive chairman.”

Private shareholders account for approximately 25 per cent of M&S’s investor base – a higher proportion than is the case in most companies – and they gave Rose overwhelming backing during the battle for control in 2004, when Sir Philip Green attempted to take over the retailer.

Lawson said that M&S had communicated well with private investors traditionally. He said: “Many of our members will be in two minds, because they are very happy with Mr Rose and what’s done, but they may be forgetting about what happened with Sir Richard Greenbury. It would be better if the company found a better way of keeping Mr Rose.”

Lawson opposed the idea that shareholders should call on Rose to stand for re-election. He said: “I think that would be a divisive way of going about things.”