Police officers guard the entrance to a housing estate on Muggleton Road, after it was confirmed that two people had been poisoned with the nerve-agent Novichok, in Amesbury. Henry Nicholls/ Reuters
Police officers guard the entrance to a housing estate on Muggleton Road, after it was confirmed that two people had been poisoned with the nerve-agent Novichok, in Amesbury. Henry Nicholls/ Reuters

Britain demands explanation from Russia after second Novichok incident