BT and Vodafone are set to lobby Boris Johnson to allow Huawei technology to be used in the UK’s 5G phone network.

BT’s chief executive, Philip Jansen, and Nick Read, his counterpart at Vodafone, are drafting a letter to the prime minister arguing they have not seen evidence that Huawei equipment poses a security risk that warrants a total ban. Huawei has always denied allegations its kit could be used by the Chinese government to spy on users.

The letter, which the two companies are considering sending to Johnson next week, also reiterates that if Huawei is banned there would be significant ramifications for the rollout of 5G.

UK telecoms operators have been happy to strip Huawei equipment from the core of their networks, where data is concentrated and security concerns are highest, which is relatively simple to replace. However, if it came to pass that Huawei equipment could not be used in radio access networks, the towers and equipment for 4G and 5G networks across the UK, the impact would be huge.

Read previously said a total ban on Huawei could put the European rollout of 5G services back by two years, as operators would have to replace it with equipment from other suppliers. The UK telecoms industry also said it would be unhealthy for the national infrastructure to rely upon two players, Huawei’s rivals Nokia and Ericsson.

The news comes as British officials have expressed frustration that the US has not been able to come up with a “plan B” alternative solution that would allow Britain not to use Huawei technology in future 5G phone networks.

Whitehall sources complain that despite intense lobbying by Donald Trump’s administration against the Chinese company, Washington has not been able to propose viable alternative technology at a similar price.

Senior US administration officials flew in on Monday to demand that the UK reverse an initial decision to allow Huawei to supply some non-core elements of the future 5G network but frustration appears to have emerged in response to their demands.

“The point is that the US have no plan B,” one British government source said. When pressed as to whether the US can suggest a technological alternative “the answer is they don’t have one”.

Huawei is the leading and cheapest supplier of 5G equipment and the UK wants mobile phone operators to be able to use its antennas and other non-core parts of the network.

However, despite official concerns, the final decision is a political one for the national security council of senior ministers meeting later this month – meaning the prevailing official advice can be overturned by politicians.

Earlier this week, Boris Johnson said it was up to Washington to propose an alternative to Huawei – although he added that he did not want to jeopardise the UK’s longstanding intelligence relationship with the US.

Speaking on Tuesday, the prime minister said: “The British public deserve to have access to the best possible technology. We want to put in gigabit broadband for everybody. Now if people oppose one brand or another then they have to tell us what’s the alternative.”

He added: “On the other hand, let’s be clear, I don’t want, as the UK prime minister, to put in any infrastructure that is going to prejudice our national security or our ability to cooperate with ‘Five Eyes’ intelligence partners [the UK, Canada, the US, New Zealand and Australia].”

The visit from the US delegation on Monday was accompanied by what they claimed was fresh information about the security risks posed by the use of the Chinese company’s equipment. But a day later British sources said that the technical warning was nothing new.

“We’d already anticipated the kind of threat that the US material demonstrates and factored that into our planning,” a British official said at the time. BT and Vodafone declined to comment.