George and Lynne are at the pub with an unnamed friend. George asks for confirmation that the friend's super sexy Russian wife was a spy. The friend says it is true but he didn't realise for many many years. They all clink glasses as someone says 'Thank goodness'.
George and Lynne's friend was married to a spy but no one knew about it. From looking at the evidence, it seems that the friend actually discovered the true identity of his wife. As she is not around, he must have decided to report her to the authorities. A governmental department, perhaps the Ministry of Defence, or the Home Office has since dealt with her for crimes against the state. She may have been deported but as relationships with the Soviet Union in the early 80s were frosty to say the least, she is most likely in jail.
When everyone is happy at the end, the initial reaction is to assume that they are celebrating the fact that the friend got a long time with his super sexy Russian wife. In reality, all three are very patriotic and sighing with relief that another insurgent has been captured. If they had their way, she would be blindfolded and face a firing squad. Unfortunately, that would most likely lead to nuclear war with the Soviet Union, so they'll have to make do with her being behind bars for the rest of her life. Cheers!