Ahead of Sue Gray's report into parties in government buildings, Laura Kuenssberg investigates what went on under Boris Johnson's roof during lockdown. Panorama follows MPs as they react to events and decide whether to support the prime minister or call for his resignation as he is fined and forced to apologise. Three former staffers who worked in Downing Street give accounts of how they attended parties, for which two of them were fined. They say there was a complete lack of social distancing and rules were routinely broken.