It said also that the Commission will consult retailers and suppliers about how best to deal with this problem. Campaigns Manager for the FPB, Matt Hardman, said that the investigation had not done enough to protect suppliers giving evidence and that only robust action would help reverse a trend of abuse.

"We saw no guarantee of anonymity for the suppliers of supermarkets in this investigation. The Commission said it would consider such requests, but that was not the cast iron guarantee that suppliers needed and was the fundamental flaw in this investigation.

"Suppliers of the supermarkets know that they are pushed too hard by the purchasing power of these giant retailers. Those unreasonable demands are not only damaging our suppliers but are then being passed down the supply chain. More must be done to make payment terms agreeable to both parties involved in contracts."

Planning changes could damage independent retailers

The FPB, which represents 25,000 small and medium-sized businesses across the UK, has warned that the UK's struggling high streets could be put at further risk from changes that might create more out-of-town and edge-of-town supermarkets.

Mr Hardman said that he would be greatly concerned for the future of smaller retailers, should such a change take place.

"Smaller retailers are already suffering as a result of increased competition from the supermarkets entering the convenience store market, so encouraging more sites away from the traditional high street, with all the advantages of free parking that they enjoy, would be a body blow for many small shops."

The Competition Commission said that planning, and the manner in which the planning regime is applied by Local Planning Authorities, act as a barrier to entry or expansion by limiting construction of new, larger grocery stores on out-of-town or edge-of-town sites. It did, however, suggest introducing a competition test into the planning process that would allow the position of existing retailers to be taken into account. Mr Hardman warned that the damage to smaller, independent shops must be taken into account, too.

"It is no good just looking at whether a new site will encourage competition between supermarkets locally, what about the independents in the area? What about the damage that could be done to them?"

Land banks must be broken up

The FPB, however, is pleased that the problem of land being held by the big supermarkets, acting as a barrier to entry to competition, has been highlighted in the provisional report. The FPB is calling for those land banks to be broken up.