Never Surrender — Clive Egleton

The nuclear deterrent had failed
While Britain had an arsenal of terrifying weapons that it dared not use, the other side only needed to use theirs once. When a Russian Scragg missile hit Bristol, Britain knew it was all over. There were some people who accepted the armistice and occupying forces without opposition, believing they were working for a better society. But for the others, the Resistance, there was never been any question of compromise.