Chinese tech giant Huawei will be excluded from providing technology for the core 5G network being developed by U.K. telecoms firm BT.
The firm's equipment will also be removed from BT's existing 3G and 4G networks. While Huawei will not be selected as a vendor for the core 5G network, it will still be eligible to provide some infrastructure support – such as phone mast antennas.
BT acquired telecoms firm EE in 2016 and will use its existing network to launch a national 5G rollout. 5G will provide superfast mobile internet access and is widely expected to revolutionize technologies such as self-driving cars and the internet of things.
In an email sent to CNBC, a BT spokesperson confirmed the process to remove Huawei equipment from the core of its 3G and 4G networks began in 2016. They said this was done as a "part of network architecture principles in place since 2006."
"We're applying these same principles to our current RFP (Request for Proposal) for 5G core infrastructure," the spokesperson explained. "As a result, Huawei have not been included in vendor selection for our 5G core. Huawei remains an important equipment provider outside the core network, and a valued innovation partner."
EE is currently trialing 5G mobile internet in London's Canary Wharf.
A Huawei spokesperson told CNBC via email the firm would continue working with BT in the 5G era.
"We hope the U.K. will continue to provide Huawei with an equitable business environment," they said. "Cybersecurity should not be politicized, and equipment vendors should not be treated differently based on country of origin."
Speaking to CNBC over the phone, a BT spokesperson said its decision was not a response to any security concerns.
However, the U.K.'s spy chief said on Monday that questions remained over Chinese firms' access to 5G networks.
"We need to decide the extent to which we are going to be comfortable with Chinese ownership of these technologies," MI6 chief Alex Younger told students at St Andrews University in Scotland.
The U.K. – along with Canada – is one of two nations in the Five Eyes security alliance not to ban Chinese telecoms firms from their 5G rollouts.
Last week, the New Zealand government excluded Huawei as a technology vendor for its 5G network, citing a "significant network security risk."
Fellow members Australia and the U.S. have also banned Chinese tech firms Huawei – and ZTE in the U.S. – from their 5G networks over fears it could make national infrastructure accessible to the Chinese government.
Both Huawei and ZTE have repeatedly denied these claims. Chinese smartphone manufacturers are subject to legislation that requires citizens and businesses to cooperate with Chinese intelligence authorities.
However, Huawei has previously stated that the Chinese government cannot legally compel telecoms firms to install backdoors or listening devices in other nations.
Eric Xu, one of the rotating chairmen at Huawei, told CNBC on Thursday that blocking Huawei from the 5G market could result in higher costs for both consumers and telecoms firms.