Mobile phone firm Vodafone is launching a fixed-line broadband service in the UK, putting it head to head with established operators such as BT.
Initially its service will be offered in Manchester, Berkshire and parts of Hampshire and Surrey.
It will offer speeds of up to 76Mbps (megabits per second), with prices ranging from £5 a month to £25.
One expert said that rivals should not be "overly concerned" about the new entrant.
Vodafone acquired the assets of Cable and Wireless in 2012 and that will form the backbone of its home broadband network.
The nationwide fibre-optic network already reaches telephone exchanges that pass nearly 20 million premises across the UK
Over the next few weeks, Essex, Hertfordshire and Yorkshire will be added to the network, with the national rollout due later in the summer.
Existing Vodafone customers can get broadband at a discount rate for the first year - a 17Mbps contract would initially cost £2.50 per month, rising to £5 after 12 months.
Customers wanting the super-fast 76Mps service would pay £10 for the first 12 months.
For non-Vodafone customers, the Vodafone Connect service will be offered in various packages:
- £10 for 17Mbps
- £20 for 38Mbps
- £25 for 76Mbps
Cindy Rose, consumer director at Vodafone, said: As the only operator in the UK which owns both a fixed and mobile network, we're in a great position to create innovative products and services that give our existing customers reasons to stay with us and new customers reasons to switch."
But Paulo Pescatore, an analyst with research firm CCS Insight, said that "rivals should not be overly concerned, for now".
He added that the firm will need to "clearly articulate benefits and features" if it wanted to succeed in a highly competitive market.
More firms are looking to join up broadband and mobile services and, in February, BT announced that it was to buy mobile firm EE.