* Ross stays as Cosalt director
* Has already quit other directorships and Olympics post (Adds detail)
LONDON, Dec 12 (Reuters) - David Ross, the co-founder of British mobile phone retailer Carphone Warehouse CPW.L, has stepped down as chairman of Cosalt Plc CSLT.L after breaching share disclosure rules.
Cosalt, which inspects and maintains life-saving equipment such as lifeboats on oil and gas rigs, said in a statement on Friday that it had asked Ross to step down but remain on the board.
"The board's decision has been taken in light of the events concerning Mr Ross' shareholding in the company and the review by the committee appointed by the board to look into them," it said.
"Whilst the board accepts that Mr Ross apparently breached certain regulations, it is currently of the view that he did so wholly unintentionally and that this in itself does not require him to step down from the board altogether."
Ross, ranked among Britain's 100 wealthiest people earlier in the year, quit as deputy chairman of Carphone Warehouse on Monday, resigned as chairman of bus and train operator National Express Group Plc (NEX.L) on Tuesday, and as a director of self-storage company Big Yellow Group Plc (BYG.L) on Thursday after a breach of share disclosure rules came to light.
He has also stepped down from the committee organising the 2012 London Olympic Games.
Reporting by James Davey, editing by Matthew Scuffham