BT has confirmed that the cost of calls to landlines and mobiles are to be capped at £10 a month for vulnerable customers.
BT Basic is aimed at people on benefits such as income-based Jobseeker's Allowance and income support and offers lower line rental costs than standard packages, with the monthly fee coming to just £5.10, rather than £18.99.
However, qualifying low-income customers have only been able to make £1.50 worth of calls each month before paying an extra 11.3p a minute if they were calling a landline.
BT has therefore updated the Basic package to ensure customers cannot be billed more than £10 a month for calls to landlines or mobiles.
This means that with line rental fees factored in, their maximum total bill will be £15.10.
Richard Neudegg, Head of Regulation at uSwitch.com, has welcomed the news, saying it will protect vulnerable, elderly and low-income households from landline bill shock, as long as they avoid ringing premium rate numbers.
"Ofcom requires BT to provide BT Basic - the telecoms equivalent of the Warm Home Discount for energy - as a condition of its historic monopoly," he commented.
"Previously, customers would only have to use their landlines for 148 minutes a month for a standard landline tariff to be more affordable than BT Basic.
"Capping standard calls at £10 a month, alongside a discounted line rental of £5.10, means vulnerable landline-only users will not have to fear using their home phone to keep in touch with people."
Mr Neudegg added that BT Basic's £4.85 broadband add-on remains capped at 12GB, which means that customers requiring more than this capped download alliance may find "a better deal elsewhere".