The Fourth Protocol is a section of a treaty signed by, among others, Britain and Russia. Under its terms, none of the signatory countries and import nuclear devices - or the components thereof - into any of the others. Russia is about to break those terms, as part of an audacious and potentially devastating plan - orchestrated by Philby himself - to place Britain under the control of a pro-Soviet Hard Left government following the election of 1987. The one, unknown flaw in their plan is that their source of secret British documents has been discovered, and the hunt for the source of the leak is going to lead the Secret Service in the direction of Plan Aurora. And even if MI5 agent John Preston can’t crack the KGB’s creative and highly efficient courier system, some devious manoeuvring within the two countries might just bring it all undone.
Forsyth throws in a lot of precise details, so the plot relies more on a slow building of tension than a rapid unfolding of events. On the upside it’s clear from the start that something fishy is going on, even if that initial something is only incidentally connected to the Russian plot. For me a lot of the appeal lies in the sheer ingenuity of the characters, both good and bad. I doubt I would ever have thought of smuggling in the two halves of a round bomb casing by disguising them as car headlamps. There’s also an unsettling and probably accurate picture of just how much bureaucracy can screw things up.
The ending was all wrapped up cleverly; maybe a little too much so, as I had to reread a couple of pages to work out exactly who had manoeuvred how and when and why. But the final twist that rounded off the epilogue was a stroke of brilliance.