The delegation told British ministers that allowing the Chinese technology giant to build on United Kingdom soil would be "nothing short of madness".
It comes after U.S. officials last night issued an extraordinary warning to Britain, insisting it would be "madness" to allow the Chinese firm to build the UK's 5G phone network.
The delegation reportedly claimed that Chinese spies, allegedly employed by the People's Liberation Army, also worked for Huawei, adding that the firm "had played a role" in supporting the "re-education camps" for the country's Muslim Uighur minority.
The FT reckons that a raft of new-in-post Cabinet ministers are now looking at it all over again, even though officials have largely agreed that economic prosperity in the post-Brexit era must take priority over national security and potentially the closeness of Britain's military and intelligence alliance with the US.More news: ‘Highly likely’ that Iran shot down Ukrainian aircraft, say leaders
"Congress has made it clear they will want an evaluation of our intelligence sharing."
The US has previously warned that any use of Huawei would lead to a review of intelligence sharing.
The U.S. has been intensely lobbying against the move, and it seems the delegation that arrived in the U.K this week was something of a last big push to steer Britain away from Huawei's 5G aspirations to build the network.
There are growing expectations that Prime Minister Boris Johnson will decide in favour of allowing the use of Huawei equipment in some "non-core" parts of the network, with a final decision due later in January, the newspaper reported. Johnson is expected to make a final decision about Huawei's involvement in the country's 5G infrastructure shortly.More news: AJ Hinch 'deeply sorry' for Astros cheating, denies direct involvement
All of Britain's 5G networks have now been launched, albeit without the Chinese firm's 5G equipment at their core.
A Huawei spokesperson said: "We are a private company which has supplied 3G, 4G and broadband equipment to the UK's telecoms companies for 15 years".
The decision on Huawei is particularly crucial as crunch post-Brexit trade talks with Washington and Brussels loom after Britain formally leaves the European Union at the end of January.More news: 50 privacy groups ask Sundar Pichai to safeguard Android users
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