BT's impending takeover of EE needs to be monitored "very closely" to ensure that it does not place the telecoms giant in a dominant market position, according to Vodafone boss Vittorio Colao.
He says there is a danger that the planned buy-out could put BT in a position to be 'restrictive' as far as enabling access to its broad range of services is concerned.
"BT will have to behave very well. As soon as the incumbent becomes such a large player in all parts of the market the temptation to become restrictive is high," Mr Colao added.
The takeover, which is partly being financed through a £1 billion share placing, will see Deutsche Telekom and Orange take 12 per cent and 4 per cent stakes in BT, and has been arranged as BT goes head-to-head with Sky over Premier League football rights in a potential £4 billion battle.
If BT wins this battle, then - combined with its increasing market share across all telecoms services - exclusivity and lack of access to content could end up suffocating the market, Mr Colao argues.
He elaborated: "The potential for BT and other incumbents like Telefonica to squeeze margins for their competitors is very tempting."
Despite the concerns raised, BT Chief Executive Gavin Patterson said the deal will allow his company to accelerate its mobility plans and increase investment in them - describing it as a "major milestone".
Currently, EE is the UK's largest mobiles provider, with 24.5 million customers, though this figure would be exceeded by Three owner Hutchison Whampoa’s proposed £10 billion takeover of O2, which would create a combined base in excess of 33 million customers.
According to Mr Patterson, the EE takeover will not see BT become dominant in the UK market, with his firm still only covering a third of the fixed-line market and a third of the mobile market. He concluded: "This deal does not concentrate the market any further and we are still a very small player in the content market."