N&P's previous chief executive, David Poole, left the company in October due to a clash of management styles. He is now suing the company for breach of contract and claiming compensation.
Mr Sims will be joining a group which has not enjoyed the best of fortunes of late. Its attempt to pioneer the warehouse club style of retailing in the UK failed and the three Cargo Club sites were sold to Sainsbury's for £45m in March The decision to sell came little more than a year after the concept's launch.
Most recently, the company has become embroiled in a squabble with its largest outside shareholder, the Dutch group SHV Makro, over a possible merger. Speculation continues that the Peacock family, which controls the lion's share of N&P stock, will sell out.
The company's recent financial performance has also concerned industry analysts. Last year's profits fell by half to £16.5m, hit by trading losses at Cargo Club and £4m costs relating to the conversion of cash-and-carry outlets to the TBW format, which also offers office supplies.
N&P says the decline in trade among independent food retailers, which form the bulk of N&P's customers, is coming to an end and that like for like, sales are increasing. It says the success of the National Lottery, launched last November, is drawing more customers into corner shops.
However, analysts remain unconvinced. One said yesterday: "It's good that they have filled the chief executive post, but we still have doubts about the overall strategy."
The shares finished 2p higher at 188p.