Mobile operator Vodafone is rumoured to be mulling a bid for UK rival T-Mobile, according to a report in the Financial Times today.

If successful the move would make Vodafone the UK's largest mobile operator, a title currently held by O2, which was acquired by Spanish telecoms giant Telefónica in 2005. But experts say UK communications regulator Ofcom could block the move to more consolidation in the mobile operator sector over competition concerns.

T-Mobile is owned by German telecoms group Deutsche Telekom, and last month announced a €1.8bn write-down at its UK operations, with predictable speculation that the UK arm would be sold.

The other UK mobile operators, 3 and Orange, make up the five UK firms all of which have been subject to the wrath of EU Telecoms Commissioner Viviane Reding in recent years as she has constantly sought to drive down mobile and data roaming charges incurred by EU citizens using mobile services abroad.

On 1 July further legislation will take a bigger chunk out of mobile operators' profits as mobile charges for SMS messages and downloading data overseas are subject to further cuts.

Industry experts say that further consolidation could ease pricing pressures in the mobile market, although it is not clear if the European Commission would attempt some sort of block on the move, if Ofcom did not.