Rupert Dickinson will stand down from his role as Grainger's chief executive from 20 October and has resigned from the company’s board for reasons of ill health.

Andrew Cunningham, Grainger’s deputy chief executive and finance director, has been appointed as the new chief executive. He has been the listed residential property company's acting chief executive since May 2009 and has been a director since 1996.

Grainger said: "Rupert has endured a difficult year involving hospitalisation and lengthy treatment. This has unfortunately rendered him unable to continue the strenuous duties as chief executive of a public company."

Dickinson started his career with Richard Ellis and joined Grainger in 1992 and became chief executive in 2002.

During his tenure the company bought Bradford Property Trust and expanded its business significantly. Grainger said that Dickinson also played an important role in the restructuring of the company last year to help take it through the current recession.

Grainger has also begun a search for a new property director and finance director.

Robin Broadhurst, chairman of Grainger, said: "Rupert has made a substantial mark on the company for which the board are very grateful. He leaves with our best wishes for the future and for a full recovery."

Grainger also said in a trading update today ahead of its results that its total group sales would be around £220m, an increase of 21.6% over the equivalent figure of £181m in 2008.

It said that as anticipated, margins have decreased because of falls in house prices and a greater proportion of investment sales (sales with a tenant in place rather than with vacant possession) and will therefore result in trading profits falling below 2008 levels.

Sales from its development division will amount to approximately £47m which is up from last year's total of £10m.

Last week it also agreed two new loan facilities totalling £615m.The forward start credit facilities have been provided so that Grainger can refinance existing loans when they expire.