Britain will respond “appropriately” if a foreign state is found to have been involved in the poisoning of a former Russian spy in England a week ago, finance minister Philip Hammond said on Sunday. “This is a police investigation and it will be evidence-led and we must go where the evidence takes us,” Hammond told BBC television. “So we have to allow the police investigation to run its course. But if there were to be an involvement of a foreign state evidenced by this investigation, then obviously that would be very serious indeed and the government would respond appropriately,” he added. Former double agent Sergei Skripal, 66, and his daughter Yulia, 33, have been in hospital in a critical condition since March 4, when they were found unconscious on a bench in the southern city of Salisbury. Reuters reported, citing British police, that a nerve agent was used against Skripal and his daughter.