UK mobile network operators T-Mobile and Orange have offered to give up 25% of their existing 1800Mhz spectrum band as a concession for allowing the proposed merger to proceed. However the FT reports that rival operators, such as O2 and Vodafone UK, believe 25% is still too little.

1800MHz is currently used for 2G voice communication services but, under Digital Britain plans, it could be opened up for use by 3G and 4G Mobile Broadband services. The combined T-Mobile and Orange operator would put 84% of the spectrum in the hands of a single company.

The Office of Fair Trading (OFT) believes that this could be anti-competitive and recently proposed a more extensive investigation by UK regulators (here), which both operators are keen to avoid.