Independent retailers are being urged to give evidence to an Office of Fair Trading investigation into the acquisition by Shell of 253 former Total sites from Rontec.

Retailers have until December 20 to provide details of sites that may be affected in the same or adjacent post code as the sites to be acquired by Shell.

The OFT enquiry is thought to be seeking to establish if any areas of local market dominance by Shell are likely to emerge as a result of the acquisition, and determine whether there is a case for the transaction to be referred to the Competition Commission.

Under terms set out by Shell, the identity of the 253 sites will not be made public and all retailers receiving information on the acquired sites should confirm in writing to the OFT that the information will only be used for the purpose of responding to the investigation and will be destroyed immediately following submission of evidence.

Concerned retailers are to email with all post codes of the sites that they believe may be affected by existing Total company-owned sites being rebranded Shell.

Once confirmed, they will then be required to complete a questionnaire and write to Carole Bowley in the mergers branch at the OFT – – confirming adherence to Shell’s terms.

The investigation is similar to that of the Morrisons take-over of Safeway in which the acquirer was forced to divest some sites to other retailers.