Beuc, the European consumer rights group, has joined the growing criticism over Google’s proposed $3.1bn acquisition of Doubleclick in an official letter to Neelie Kroes, the European Commissioner.

Jim Murray, director of Beuc, wrote to the European Commission last week, warning that the proposed deal – which would bring together the world’s largest search engine with online advertising group DoubleClick – “may have a negative impact on the selection of online content available to consumers and on privacy”.