Roddy Ho is used to being the one the slow horses turn to when they need miracles performed, and he’s always been Jackson Lamb’s Number Two. So when Lamb has a photograph that needs doctoring, it’s Ho he entrusts with the task. Christmas is a time for memories, but Lamb doesn’t do memories – or so he says. But what is it about the photo that makes him want to alter it? How would the slow horses cope if Roddy Ho didn’t exist? And most importantly of all, are the team having Christmas drinks, and if so, where?

Standing by the Wall offers a glimpse into the kind of seasonal merriment you might expect at Slough House, where the boss generally marks the festive season with an increase in hostilities. But then, this is the secret service, not Secret Santa. And the slow horses aren’t here to enjoy themselves.