Based on the evidence of this book, which I have just finished reading, the formula seems pretty simple: Take a maverick assassin with IRA connections, some East End organised crime figures one of whom must be gay, and a few token real-life figures (if John Major can be so described). Have the assassin go through a Judas gate a few times, mix well with Bushmills whiskey and a light aircraft. Add a visit to the Channel Islands and a naively adoring adolescent girl who develops an unrequited passion for the assassin. Simmer lightly for 200 pages and then, "Hey presto", another best-seller. Not totally unenjoyable, though.