The Competition Commission denied this week that a failure to find a planning expert was responsible for a three-month delay to the inquiry.

The Commission was hoping to hire an expert to advise the members of the inquiry on planning issues, but the search has been hampered by conflicts of interest among the proposed candidates.

"Every candidate the Commission has so far proposed to the supermarkets has resulted in an objection [from one of the multiples], due to previous work the expert may have carried out for a rival," said a senior source at one of the big four. "It's a major headache for the inquiry."

A leading planning expert confirmed the predicament. "Planning consultants are reluctant to help with this type of inquiry because the supermarkets may be clients or they will want them as future clients.

"Likewise it is hard to find a local government planning expert without a conflict of interest."

However, the expert added it was not an impossible task. "There are people out there that would be ideal to help. A retired planning officer, for example."

The Competition Commission admitted its search for an expert was still ongoing but denied this was adversely affecting the speed of the inquiry. "We are well versed in getting to the bottom of a range of issues in many markets," said a Commission spokesman. "We're confident we'll gain the necessary understanding in this inquiry, irrespective of whether we actually hire someone - there are many other ways we can achieve this." He said the report would be published in February 2008 now and that no single factor had led to the delay.

Nevertheless, with planning playing such a key role in this inquiry, one retail source said it was a major hurdle and was bound to have a knock-on effect.

The inquiry involved "fiendishly complicated" issues around planning and market definitions, added Alastair Gorrie, competition partner at law firm Orrick.

The mass of evidence being submitted following Emerging Thinking in January had made it impractical to stick to the original timescale, he said. "A lack of due process, or coming up with a totally unreasonable conclusion, could lead to a judicial review."

The Commission has also been hampered by a lack of co-operation from suppliers. It has admitted that having approached 40 suppliers in October, it still only had 15 usable responses (The Grocer, 31 March).

The inquiry was further complicated last week by Tesco's submission arguing for a 30- minute drive time radius from a store (The Grocer, 7 April). However, in working papers published this week, the Commission appeared to signal it would stick to a 10-minute drive time local market definition. Its analysis showed a store's margins decline as the number of rivals in a 10-minute drivetime increased, but the effect lessened with a greater drive time.

Justin King, CEO of Sainsbury's said the important factor was not the speed but the fact the Commission was listening. "We want them to conduct the inquiry quickly, but would rather they conducted it properly and well first."

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