The question over its relationship with the Chinese state came up again with a recent study written by Christopher Balding, Associate Professor at Fulbright University Vietnam.

"Using a unique dataset of CVs", he found that "key mid-level technical personnel employed by Huawei have strong backgrounds in work closely associated with intelligence gathering and military activities."

"Based upon an analysis of this dataset, I find there is strong evidence that Huawei personnel act at the direction of Chinese state intelligence, and that there exists a deep and lasting relationship between Huawei, its employees, and the Chinese state." he writes.

When asked about the study by the BBC, Huawei said it maintains "strict policies" for hiring candidates with military or government backgrounds and cyber security remained a top priority.

"We welcome professional and fact-based reporting on investigations into Huawei's transparency," Huawei said in an e-mailed statement.

"We hope that any further research papers will contain less conjecture when drawing their conclusions, and avoid so many speculative statements about what Professor Balding 'believes', 'infers', and 'cannot rule out'."