Major United Kingdom mobile operators have come out against a full ban on Huawei in the country, and have asked the government to ensure that any decision to restrict the Chinese company is "evidence-based".
Network providers including BT Group and Hong Kong-based Three shared their views with a parliamentary committee on national security, which is currently carrying out an inquiry on British network infrastructure.
The UK is under pressure to join a boycott of Huawei led by the United States, which alleges that the company has and will continue to plant back doors that enable Chinese surveillance.
BT pointed out that the UK National Cyber Security Centre has not found or been provided with any evidence to support these claims.
"We would therefore urge the government to take a proportionate and evidence-based decision that maintains a competitive telecoms supply chain," BT said in a written statement.
BT said it has already agreed to omit Huawei equipment from core areas of its network, and also outlined outgoing work carried out by the NCSC and the UK Huawei Cyber Security Evaluation Centre to ensure the safety and security of UK networks.
"We do not view a ban on using Huawei in access networks as a proportionate response, given the range of protections in place," BT said.
Huawei is a leading global supplier of telecommunications hardware, and the company's equipment is already in use throughout UK networks.
Last week, BT CEO Philip Jansen warned that the complete removal of existing Huawei units from British infrastructure would take around seven years.
And Three said that a ban on the company would significantly delay the UK launch of 5G.
"It is essential that any assessment of the supply chain, and any resulting policies, take a balanced view, are evidence-based and give the UK the best chance of realizing our 5G ambitions," Three said in a statement.
Mobile UK, which is the trade association for network operators EE, Telefonica, O2, Three and Vodafone, said a delayed 5G rollout would cost the British economy between 4.5 billion ($5.8 billion) and 6.8 billion pounds.
"The UK will also suffer in terms of lower inward investment and lost productivity gains through the stagnation of digital infrastructure," Mobile UK said in a statement.
The committee also heard from sources in favor of a ban, including Martijn Rasser, a senior fellow at the Center for a New American Security in Washington.
"Her Majesty's Government should not allow Huawei equipment on its 5G networks," Rasser said.
He outlined a number of concerns including "the company's opacity", Huawei's "relationship with the Chinese government", and "the general espionage risk associated with Chinese technology firms".
Despite pressure from the US, major economies in mainland Europe, including France and Germany, look set to work with Huawei on 5G.
In network security draft rules released on Wednesday, Berlin indicated that Huawei will be able to bid on German 5G contracts.
Huawei, which has long held that the US boycott is politically motivated, praised the German government.
"Politicizing cybersecurity will only hinder technology development and social progress while doing nothing to address the security challenges all countries face," Huawei said in a statement.
In May, French President Em?manuel Macron said he does not intend to ban Huawei.
"Our perspective is not to block Huawei or any company," Macron said. "France and Europe are pragmatic and realistic. We do believe in cooperation and multilateralism."