If you buy your cigs in an EU country and you buy duty paid not duty free then you are allowed to bring 1300 per person into the UK. If you buy at duty free shops or Gibralter Canaries then you are only allowed 200per person. If you buy onboard ship then they will be duty free and you will only be allowed 200. Be careful as the customs are always very keen we have seen numerous people being caught with duty free cigs.

No one can tell you, since you do not tell us where you are purchasing your cigarettes. Rules for EEC countries and non-EEC countries differ quite markedly.