BT, the UK fixed-line incumbent, is reportedly set to announce an aggressive return to the consumer mobile market, with 4G offers aimed at undercutting key rivals.

The service, said to be called BT Mobile, will be delivered through an MVNO deal with EE, which was signed in October 2013 (well before BT agreed a £12.5 billion takeover of the UK’s largest mobile operator).

It is believed BT will primarily target its mobile offering at existing customers, so stoking the market further for bundled packages of fixed and mobile products.

Although BT gives away its sports TV channels for free to entice broadband customers, the Financial Times reports that the operator will not be giving away mobile services in the same way.

Nonetheless, it seems likely that BT’s mobile subscribers will be lured by free premium content. The Telegraph pointed out that BT executives have hinted in the past that the operator will repeat its strategy in the pay-TV market, where it offers Premier League football for free to broadband subscribers.

The same UK newspaper, quoting “industry sources”, said BT would undercut 4G packages from main rivals – O2, Vodafone, and even EE – but services would not be as cheap as first feared.

Apparently there is no intention of matching the lowest offers from 3 UK, the smallest mobile network operator, which starts 4G pricing at £11 per month.

The Telegraph said BT is planning to delay its big marketing push until the summer, after the current football season ends.

Moreover, the service will be offered on a SIM-only basis.

If the deal with EE gets green light from regulators – which is expected by the end of the year – BT will then of course have access to EE’s retails stores. With that in mind, BT has less incentive to pile lots of resources now into selling devices.

By launching the service this week, BT CEO Gavin Patterson makes good on his promise to launch a consumer mobile play before the end of the operator’s current financial year (31 March).

The UK’s Competition and Markets Authority has already started an ‘informal’ inquiry into the BT/EE merger, inviting responses from rival operators about they think the potential market impact might be.

According to the FT, UK-based infrastructure player CityFibre has already said that the BT/EE deal could prove bad for competition, citing fears over its own deal to provide backhaul connectivity to the mobile player.

CityFibre announced a deal with EE and 3 UK’s MBNL partnership in November 2014, to provide connectivity starting with a project in Kingston-Upon-Hull. With EE forming part of an enlarged BT, CityFibre would be likely to lose a lucrative customer for its own network.