There have been at least 8 between Litvinenko and Skripal. https://www.buzzfeed.com/heidiblake/from-russia-with-blood-14-suspected-hits-on-british-soil?utm_ter

There have been at least 8 between Litvinenko and Skripal. https://www.buzzfeed.com/heidiblake/from-russia-with-blood-14-suspected-hits-on-british-soil?utm_term=.qxKNwwvan#.ojOq00yrY https://www.buzzfeed.com/heidiblake/from-russia-with-blood-1...