Devon County Council decided to sell its airport shares last year

The European Commission has referred the case back to the UK amid fears the sale could threaten competition in the South West's air travel industry.

The council hopes to sell it to Macquarie, the firm that runs Bristol Airport, and Ferrovial Aeropuertos.

But there are concerns the move is anti-competitive and will mean Exeter will be reduced to a support role.

Fears have been expressed by other bidders and South West Euro MPs that competition will be reduced.

The OFT, which can block the sale, has already expressed an interest in investigating the sale which is expected to take three months.

Macquarie Airport Group (MAG) also jointly controls the Rome airports and Brussels Airport and has shares in Birmingham Airport and Copenhagen Airport.

Together with Ferrovial, MAG jointly controls Bristol Airport.

Apart from its stake in Bristol Airport, Ferrovial has investments in Sydney Airport, Belfast City Airport and Antofagasta Airport.