Salisbury becomes the scene of a major international incident. Sergei Skripal and his daughter Yulia are found poisoned on a park bench. Then, an astonishing discovery: he’s a former Russian spy and they've been poisoned with Novichok, one of the deadliest substances in the world. Parts of Salisbury are locked down as police try to find the poison. Presenters: Andy Howard, Marie Lennon Reporter: Dan O’Brien Producers: Andy Howard, Marie Lennon, Tom Ryan, Dan O'Brien, Rachael Smith Executive Producers: Mary Sanders, Naomi Wordley Consultant: Jake Williams Commissioning Editor: Alistair Miskin