BT removed Huawei gear from core network functions following its acquisition of EE three years ago, according to The Financial Times.
The report says BT will also avoid the use of Huawei gear in its 5G core although it may use other infrastructure products from Huawei. This follows warnings from British intelligence agencies that Huawei could pose a national security risk. No technical details were reported.
https://www.ft.com/content/c639aaf4-f7c9-11e8-8b7c-6fa24bd5409c