Theresa May has approved Huawei's bid to help build Britain's 5G network, despite warnings about the risk posed to national security.
The Chinese telecoms giant has been granted restricted access to build "non-core" infrastructure such as antennas, Whitehall sources have confirmed.
However, it will be blocked from involvement in the most sensitive areas of the network.
This permission came from the National Security Council, which is chaired by the prime minister, on Tuesday.
The move comes just days after Huawei was accused by US intelligence of being funded by Chinese state security and almost a month after Britain's National Cyber Security Centre said the company posed a threat to national security.
It also comes despite concerns expressed by other members of the Five Eyes intelligence-sharing group: the US, Canada, Australia and New Zealand.
The US, Australia and New Zealand have barred Huawei from supplying key elements of their infrastructure and Canada is still considering the matter.
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