By Jonathan Davies

BT has confirmed its plans to return to the mobile phone market, a decade after leaving it.

BT will launch its 4G service with a £5 discount for existing broadband customers, and will use two spectrums - one that it owns, and one owned by EE, which it is trying to buy.

The telecoms giant is also hoping to lure football fans, by offering them the ability to watch live BT Sport Premier League fixtures via an app, even if they're not BT broadband customers.

"An entry tariff of £5 a month will grab headlines, but inclusive access to BT Sport and five million wi-fi hotspots offers important differentiation in a cut-throat field," said Ben Wood, from telecoms consultancy CCS Insight.

"We expect initial low-key marketing to heat up as BT makes a broader assault on the bundled telecom market over the summer."

BT has only revealed prices for SIM-only deals, but said it would reveal more details following its proposed £12.5bn takeover of EE.

BT is widely credited as one of the leading figures in mobile phones during the 1980s through the Cellnet network. A decade ago, it sold the network to Spanish telecoms firm Telefonica, creating O2. The owner of Three has agreed to buy O2 in a £10bn deal.