https://www.bbc.com/news/technology-47800000
"It was introduced at the manufacture stage but the path by which it came to be there is unknown and the fact that it looks like an exploit that is linked to the NSA doesn't mean anything," Prof Woodward said.
"It could be organised crime gangs, which are increasingly interfering with the supply chain, or it could be someone playing geo-politics to discredit Huawei.
"There is no evidence that the company has done anything malicious or any evidence they were under pressure from the state."
The question remains, however, according to Prof Woodward: "How did the software engineering processes allow this on?