Brussels, 26/08/2002 (Agence Europe) - Callum Mc Carthy, Director General of OFGEM, the office that regulates energy markets in Great Britain, has urged the European Commission to conduct an investigation into the merger, worth US$ 10.1 billion, between the energy giant E.ON and the country's biggest gas supplier, Ruhrgas, approved in July by the German authorities. The request has the backing of Brian Wilson, UK Energy Minister, who, according to Reuters, has also called on the Commission to review the operation. The UK Government and a number of industrial parties in Germany and other countries fear that the merger will give E.ON and Ruhrgas a stranglehold on the German gas market and control over sales to consumers and to gas pipeline networks. However, since the merger was announced, the Commission has refused to conduct an inquiry into the operation. It maintains that, at the time of the announcement, the companies did not earn a sufficiently high proportion of their turnover outside of Germany to warrant an investigation by its services. So the Commission has left the matter to the German authorities. Reuters reports that, for Mr McCarthy, Germany plays a key role in secure energy supplies. He commented that, in today's European market, and with enlargement on the horizon, gas and electricity must inevitably cross Germany. So it is very important to ensure that there is free access and that costs are not excessive. Moreover, the European Council of Energy Regulators has written to Commissioners Loyola de Palacio (energy) and Mario Monti (competition) to express concern over the growing number of dominant companies in the energy sector in Europe. "Mrs de Palacio and Mr Monti will answer these letters," announced a Commission spokesman on Thursday, adding that: "The Commission's proposal on liberalisation of the energy markets has been tabled. It is for the Member States to accept their responsibilities."