An £800 tax would fund old diesel scrappage, encourage move to low-emission vehicles and reduce air pollution, according to Policy Exchange thinktank An £800 pollution tax should be put on sales of new diesel cars, with the proceeds used for a scrappage scheme for older diesels, according to the thinktank Policy Exchange. The move, proposed ahead of George Osborne’s budget on 16 March, would encourage motorists to move towards lower emission vehicles and significantly reduce air pollution, according…