Britain and its allies said only Russia would have the ‘means, motive and disregard’ to launch such an attack – as his widow calls for Putin to be held accountable On The Ground newsletter: Get a weekly dispatch from our international correspondents Get a weekly dispatch from our international correspondents Get a weekly international news dispatch Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy notice Putin arch-rival Alexei