In an op-ed in the UK's Financial Times, Robert Hannigan, who served GCHQ from 2014-17, said the chorus of voices calling for Chinese firms to be locked out of telecommunications networks in Western countries cited a number of concerns all of which were lumped together under a perceived cyber threat which could only be countered by a total ban.
But, he said, these arguments "are short on technical understanding of cyber security and the complexities of 5G architecture".
The US has been campaigning for at least the last two years to try and get countries that it considers allies not to use Huawei equipment in the rollout of 5G networks. Australia has bowed to these wishes, as has New Zealand.
While the American allegations against Huawei, accusing the Chinese telecommunications vendor of violating its sanctions against Iran were not trivial, Hannigan said they had nothing to do with telephony or cyber attacks. He added that if Huawei was found to have indeed violated these sanctions, then the company would meet with the same penalties as some well-known British banks.
Hannigan said Britain had a unique way to evaluate any possible risk from Huawei to the UK's telecommunications networks – through the Huawei Cyber Security Evaluation Centre, a testing centre set up by the company and jointly run with the UK's National Cyber Security Centre.
"The GCHQ-vetted facility, which has been evaluating Huawei’s presence in UK telecom networks for some years, has given us a detailed insight into the company’s hardware, code, processes and policies," Hannigan wrote. "No other Western government has this."
He said that certain issues had been identified in recent years and the company had said it would expend the necessary money and put in the technical talent needed to sort out these issues. "Huawei has reportedly promised to address the criticisms and to spend huge sums doing so. The NCSC should wait and see how well it delivers," Hannigan wrote.
But, he said, the key point, which had been obscured by the hysteria over Chinese technology "is that the NCSC has never found evidence of malicious Chinese state cyber activity through Huawei".
"It is not naive: it has, for example, pointed to the scale of Chinese state-linked cyber espionage through attacks on IT-managed service providers around the world. But the fact that these attacks did not require the manipulation of Chinese sovereign companies such as Huawei merely underlines how ineffective a blanket security ban based on company national flags is likely to be."
Hannigan said those who were "running for cover from Chinese companies", after welcoming inward investments with open arms all these years, were acting as though the fact that China was run by a Communist government was something not known until now, as also the fact that the party could reach "if it wishes, into every part of the Chinese private sector".
"But most of us had priced that into our threat calculations long ago; I expect China does the same in reverse," he added.
Maintaining a clear head about these facts would help factor in the risk when incorporating Chinese technology into networks, Hannigan said, adding that "sensible restrictions" on where such technology was deployed and ensuring there was no single point of failure were ways to manage any risk.
"But assertions that any Chinese technology in any part of a 5G network represents an unacceptable risk are nonsense," he said, adding that Western countries should accept that China would be a global tech power in the future and start managing the risk immediately, rather than pretend that the West could turn a blind eye to China's inevitable technological rise.