Leave campaign's £350m claim was too low, says Boris Johnson

Foreign secretary says campaign ‘grossly underestimated’ amount of money UK sends each week to EUBoris Johnson has ratcheted-up his defence of Vote Leave’s infamous assertion on the side of their bus that Britain sends £350m a week to the EU by saying the group could have used a much higher figure.The foreign secretary said the UK’s weekly gross contribution would rise to £438m by the end of a post-Brexit transition period and insisted leave campaigners were r