BT said the launch of the service has only become possible due to improvement in large processing power so that its systems can proactively divert calls before they reach a customer by recognising when a rogue number is making huge volumes of calls.
Furthermore, the service will let customers refer nuisance numbers to the firm's database to try and stop unwanted calls getting through. They can do this by dialling 1572 after a nuisance call, or going online and logging the number.
This will stop that number being put through again, and if large numbers start to report it then it will be added to BT's database too.
John Petter, chief executive of BT Consumer, said the project would ensure customers had "the means to fight back against the millions of unwanted calls": "We're declaring war on the companies that regularly pester our customers with nuisance calls on subjects such as PPI and personal accident claims."
The government has given its backing to the scheme, with Matt Hancock, minister of State for Digital and Culture welcoming the move by BT.
"We've forced companies to display their numbers when they call you, made it easier to prosecute those involved in making the calls, and increased the maximum fines up to £500,000," he said.
"We welcome BT's new service, which offers customers an additional level of protection, helping them to fight back against this ongoing harassment."
To underline the scale of the problem BT also published data showing how many nuisance calls were logged in a single week during December, with PPI calls still dominating the time spent wasted on the phone.
TalkTalk, which has been offering similar technology for three years, welcomed the arrival of BT into its call-blocking gang.
"We now block 92 million unwanted sales, marketing and scam calls a month from reaching TalkTalk homes, which is double the amount we blocked last year.
"We're pleased to see other providers follow our lead in taking a stand against nuisance calls as this is an urgent problem, which consumers shouldn't have to tackle alone."
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