BT has moved a step closer to severing ties with Huawei by picking Nokia to upgrade its mobile network to 5G.
The telecoms giant, which owns mobile operator EE, will use Nokia kit for more than 11,000 masts nationally, extending a deal covering London and the Midlands.
Nokia will also replace Huawei equipment in BT's 2G and 4G network following the government decision in July to ban the Chinese company.
Prime minister Boris Johnson has blocked Britain's mobile and broadband operators from buying Huawei kit and ordered existing equipment be removed by 2027.
It came after US sanctions on Huawei prompted a review by the National Security Council, which found such penalties could harm the UK's supply chain.
Huawei is one of the world's biggest telecoms equipment suppliers, but rivals have gained ground since America urged countries to outlaw the company over Chinese spying fears.
Nokia equipment counts for about 30pc of BT's radio access network, with Huawei making up the rest.
The deal will see Nokia become BT's biggest equipment provider, supplying more than 60pc by expanding its supply to Aberdeen, Cambridge and Brighton.
That means Nokia equipment will be installed in 11,600 radio sites.
It is an early win for Nokia's new chief executive Pekka Lundmark, who joined the Finnish giant at the beginning of the month from energy firm Fortum.
Nokia had the second biggest share of the telecoms equipment market at 15pc in the first three months of the year, according to telecoms analysts Dell'Oro Group.
That is still lower than Huawei, which had 28pc of the total revenue share over the same period.
Nokia's deal with BT will also see it work on OpenRan, a new technology standard that lowers costs by opening up mobile phone infrastructure to a wider range of suppliers.
BT chief executive Philip Jansen said digital connectivity was "critical to the UK's economic future, creating jobs and underpinning sustainable growth".
Nokia rival Ericsson inked a deal with BT in April to supply 4G and 5G equipment to the core of the network.
A second BT contract to support its 5G rollout is likely to go to Ericsson, although no deal has been confirmed by either company.