Independent research conducted by National Accident Helpline found that more than half of people find these cold calls distressing, while the ICO has said they received more than 180,000 complaints between 2014 and 2015.
The telecoms giant will monitor calls made to its domestic customers and look to identify patterns in calling, diverting ‘rogue’ numbers into a junk voicebox.
BT’s customers will also be able to divert nuisance callers themselves using their own ‘blacklist’.
It plans to launch the service later this year and is following the lead of Talk Talk, which already bars certain calls for free while blocking millions more centrally.
John Petter, chief executive of BT Consumer, said: “We are giving control of the landline back to our customers; we are working to identify those calls.”
Mr Petter called on other providers to fight back against nuisance calls.
He said: “They can help us to root out the malicious players they may be hosting on their own networks when we identify suspicious behaviour.”
However, telecom expert James Barford, from Enders Analysis, thinks it may be easier said than done to differentiate between nuisance and important calls that originate from unknown numbers.
“It is a positive move from BT but it will be hard to define what is junk,” he said.
“For example, a call from HMRC would be important, as are many other calls that are not strictly ‘personal’.”
An Ofcom spokesman said: “We welcome BT’s plans to intercept nuisance calls on its network and reduce the harm caused to consumers.”
