...and Great Britain is not a member of the EU. Not sure if you genuinely believe that NI will remain in the EU whatever the result or whether you are being rather pedantic about the OP using GB rather than UK!
In 1990 English clubs had been banned from Europe for 5 years and so were not corrupted by the pernicious continental influence. In 1996 the tournament was in England and so semis was a minimum requirement.
Or possibly something to make people vote leave...fewer foreign players, more British players getting into top teams and once again England becomes a force in world football. The evidence is there: 1966 England win; 1970 England narrowly beaten quarter-finalists; 1973 join EEC; 1974 fail to qualify.