Former Marks & Spencer boss Sir Richard Greenbury today came out battling for its current executive chairman Sir Stuart Rose ahead of what is set to be a rowdy shareholder meeting on Wednesday.

Greenbury, who was chief executive of M&S from 1988 to 1999, claimed there was a “vendetta” against Rose and said that he could not identify anyone “big enough” to take over from Rose when he steps down.

At least a fifth and possibly as many as half of M&S shareholders are predicted to back a motion at this week's annual meeting at the Royal Festival Hall calling for the retailer to fast-track the appointment of a new independent chairman.

“I feel that this continued attacking is irrelevant to the point of being vindictive,” said Greenbury, 72. “Stuart Rose has done an excellent job after six years of decline under three failed chief executives.

“This is the worst recession since the early 1990s and this is not the time to fiddle and piddle around what someone's job title is.”

Greenbury went on to claim that the corporate governance rules which recommend the separation of the roles of chairman and chief executive had not worked in many cases.

He said: “It failed in terms of GEC, Royal Bank of Scotland, HBOS, Northern Rock and Bradford & Bingley It has failed in a very large number of cases where companies have separated the roles. Shareholders should be flexible.”

Wednesday's vote is on an advisory motion which needs the backing of 75% of voting shareholders for it to become binding, which is extremely unlikely to happen.

The current plans by the M&S board, led by senior non-executive director Sir David Michels, are to appoint a new chief executive next year with Rose retiring as chairman during 2011. Greenbury said that the choice of the new chief executive was far more important than the debate over Rose's roles. “The biggest concern that I have is that every effort has to go to finding a good chief executive and that the board handles that in a measured way and makes the right judgment.”