Russia-UK tensions rise over spy poisoning

Britain has rejected Russia's call for a joint investigation into a nerve agent attack on former double agent Sergei Skripal in Salisbury last month - calling it a perverse and diversionary tactic.

Moscow made the request at an emergency meeting of the OPCW - the chemical watchdog looking into the incident.

A combined total of 342 diplomats have been expelled and sent back to their home countries since the alleged attack.

Al Jazeera's Laurence Lee reports from London.