The Summer of Love — Richard Hernaman Allen

1967 - "Summer of Love" and an escalating war in Vietnam. The British want to do a deal with the US to acquire high-tech computer knowledge, but the US fears it will be leaked to the USSR. Nick Storey is tasked with checking the security of UK export controls. He begins to get messages containing vague threats. After he completes his initial findings, he comes home to find his flat attacked by a rocket grenade and Rosemary apparently killed. To identify the killers, he must break many of the rules, including co-operating with the East Germans, going on an anti-Vietnam war demo, confronting a rogue US agent and finally laying a trap for a spy in the heart of Government.
Following "The Waterguard", this is the second book in Richard Hernaman Allen's series set in HM Customs & Excise.