LONDON (Reuters) - Britain with work with its international partners to hold Russia to account over its detention of opposition leader Alexei Navalny, a spokesman for Prime Minister Boris Johnson said on Tuesday. Asked whether the government was considering imposing sanctions on the owner of the Chelsea soccer team Roman Abramovich, reported to be one of Navalny’s demands if he is not released from prison, the spokesman said: “We will continue to monitor the situation closely and continue to work with OPCW (the Organisation for the Prohibition of Chemical Weapons) and our international partners to hold Russia to account.”