Non-cooperation with U.S. surveillance is most likely. For years, the U.S. Government has 
blocked Huawei from our networks “the conviction in Washington that the company has undisclosed connections with the Chinese government, and suspicions that Huawei equipment could surreptitiously harbor software to facilitate cyberwarfare, including espionage or network disruption.” http://lat.ms/13ovkia It’s easy for D.C. to make the assumption Huawei cooperates with China. After all, Cisco, Alcatel-Lucent, Nokia and Ericsson have long had very close ties with the U.S. & European governments. That’s one of the reasons the NSA and GCHQ are so effective.
But after six years of investigation, there’s no evidence Huawei is helping spy. The U.S. and UK agencies looking for that evidence are exceptionally effective, as Ed Snowden demonstrated. The odds are they haven’t found anything because there is nothing to find. Which raises the questions, Why is the U.S. so strong blocking?
The best answer I’ve heard is the problem is not that Huawei is spying but that Huawei is unacceptable because they don’t spy – for the U.S.
I have only rumor and not a reliable source, but this makes sense. The near-ubiquitous U.S. and U.K. pervasive results strongly suggest we’ve cracked Huawei gear in Europe anyway, but it’s surely easier with the cooperation provided by Cisco, Juniper & Alcatel.
Hiltzik’s LAT article reports the U.S. evidence i”was long on innuendo and short on hard information” and pointed to “commercial xenophobia” as another possible explanation.