Downer EDI has been blasted by Allan Gray, one of its biggest investors, for being “inept” and not rolling more heads after the services group issued another profit warning that caused its stock to plummet 24 per cent on Monday.

Allan Gray managing director Simon Mawhinney, who oversees a 6 per cent investment stake in the contractor, has written to Downer chairman Mark Chellew asking for a meeting after the company’s interim net profits fell 21 per cent to $68.1 million, and it cut its annual profit guidance for the second time in two months and slashed its dividend.