British designed, made, supported product
Of all the vendors, the following springs to mind:
A) Motorola, now defunct, did a lot of design work in Swindon for many years. Unfortunately, bad strategic decisions (coincidentally some involving a partnership with Huawei) sank that ship. Remnants swallowed by Nokia-Siemens before being axed.
B) Alcatel-Lucent also had a design bit in Swindon, partly subservient to France, of course, but it was there. Swallowed by Nokia, axed
C) Nokia used to have a design function in Camberley, near J9 of M25. Not sure of its fate.
D) Panasonic have/had something in mobile networks in the M4/3 corridor, no idea what though
No idea about any Ericsson presence
In short, there used to be a lot of mobile network infrastructure expertise in the M4 corridor. Shame the toilet flushed on it in the race to get the lowest bidder