The media coverage at the time (which I followed closely because I worked in this space) indicated that the UK was under a great deal of pressure from the US to ban Huawei. The US was allegedly concerned that the use of Huawei equipment would allow US/UK shared intelligence to be eavesdropped by the CCP. The US pressure was widely viewed in the UK as having an economic purpose disguised as security.
A quick search found: https://www.euractiv.com/section/politics/short_news/uk-bann...