Government officials are taking legal advice on whether the new supermarket planning test proposed by the competition regulator will require primary legislation.

Building has learned that the fascia test proposed by the Competition Commission as the result of its enquiry in the groceries sector may require an act of parliament.

The Competition Commission proposes that all new supermarket stores be subject to a test to ascertain whether they already have a market dominance in that locality. This would require the communities department to designate the Office of Fair Trading a statutory consultee in the planning process.

The sticking point, however, is thought to be in using the planning process to determine a matter – market dominance by a retailer – that has nothing to do with land use, but instead the identity of the land occupier.

Two sources said the communities department has reservations about the proposal and is taking legal advice on the issue. The Competition Commission has already been persuaded to make an exception to the rule for regeneration schemes.

Rynd Smith, policy and practice director at the Royal Town Planning Institute, said: “We have concerns that this test moves away from the principle to the personal. We’d strongly advise the government not to go ahead with this without good legal advice, otherwise it could be challenged.”