Mobile broadband provider 3 UK has reiterated its concerns over the proposed merger of rival firms T-Mobile and Orange.

The move, which was first reported in November 2009, would raise short and long-term competitive issues, according to 3 UK Chief Executive Kevin Russell.

He said it is right that the Office of Fair Trading scrutinises the potential impacts of any joint venture on the UK market, where the effects are likely to be felt the most.

Mr Russell explained that the proposed merger could lead to a concentration of 84 per cent of the UK's 1800Mhz radio spectrum in the hands of a single company – potentially proving obstructive to the government's Digital Britain vision.

"For the merger to take place without significant harm to consumers and competition, we believe the merged operator should be required to release at least a third of the 1800Mhz spectrum it currently leases," he said.

Last month, Mr Russell told the Financial Times that the merger should be considered by a British, rather than European regulator.