Antitrust authorities in Spain have struck a blow to Gas Natural’s planned takeover of Endesa, saying the move would cause ‘irreversible' damage to the national energy market.

The TDC antitrust court said that even with conditions, the deal would be inappropriate and its full report recommends that the government rule against the deal, although its own ruling is not binding.

Gas Natural has proposed asset disposals that will see Endesa generation transferred to Iberdrola, but the TDC finds this is not enough to resolve competition issues.

The report has now been delivered to the Finance Ministry, which will make its own recommendation to the Spanish Cabinet of Ministers. The government is then due to decide on the takeover within the next month, but despite the antitrust concerns, the Socialist government is thought to favour the deal. However, the TDC decision is expected to add weight to the anticipated legal challenges from Endesa, which has vowed to fight the takeover tooth and nail.