#10, LFNI: UK avionics demise due to: the prevalence of multi-nation aircraft programmes where political necessity forced a third-party avionics choice, and the late take-up of advanced semi-conductor technology in the UK. No demise: Smiths thrives in GE Aviation Systems, much of Ferranti and Elliott in SELEX/Finmeccanica.
No late take-up: Cat.IIIa, 12ft. decision height Autoland, Smiths on Trident/Belfast, Elliott on 1-11/VC10, slaved to Leader Cable at Brize Norton/LHR. First to market, where all then lapsed, in part due to clean-air removal of "dirty" coal (pea-souper smog now a dim memory), and in part to late-1950s' galloping pace of (now, IT): Autoland's early-1950s' origins at Bedford BLEU involved valves. TSR.2, Concorde, Sea Slug/Bloodhound/Thunderbird Mks.I SAMs were all adversely impacted by step-change in Automatic Data Processing. 1962 Bloodhound I "Affair": Ferranti had won pulse radar guidance, paid by MoS in 1953/4 to take licences from (AT&T)Bell Labs and Texas Insts. and thus become Europe’s 1st. supplier of silicon diodes by diffusion process. Fairchild’s planar/Bell’s epitaxial processes, ’58/60 led in ’61 to TI/Fairchild launch of medium-scale integrated circuits, applied by Ferranti in Bloodhound, omitting to mention it to MoA's pricers. £4Mn. repaid. They still won much on Tornado. Of 1960s' International Collaborative Projects (the alternative to which was no projects) Concorde was extensively Brit avionics; Jaguar 'S' had Elliott NAVWASS; Lynx has Elliott AFCS even in the Aeronavale variant. Tornado IDS was Elliott AFCS, TF 'E' scope and TV Tabular Display; Smiths HUD. Your 3rd. party choice point is presumably Elliott/Ferranti's loss of the Tornado Ground Mapping and Terrain Following Radars to TI, in R&D (they licensed their production/support). Both teams recovered from that setback. The digital data bus funded into Tornado, 1971, was in no way inferior to F-111A, F-15A. In exchange for US lead on the radar, FRG granted UK "excess" share of the rest of Tornado's common avionics suite, to UK's great benefit on Eurofighter.