Cigarretes are realy cheap in Gibraltar! We were there recently, during our summer cruise, and we bought about 2000 cigarretes. No problem taking cigarretes into the ship (our ship was Thomson Celebration), however if at the airport when you come home they may check your bags and make you pay the taxes.
When travelling from a non-EU country (including the Canary Islands, the Channel islands and Gibraltar) you can bring the following into the UK for your own use without paying UK tax or duty:
200 cigarettes; or 100 cigarillos; or 50 cigars; or 250g of tobacco
Outside the EC allowances vary. To check allowances, visit the Customs & Excise website on www.hmce.gov.uk. Purchases made on the ship are subject to non- EC regulations - check on board for what you are allowed to bring home.
For info cigarettes are less than a pound a pack in Gibralta.
Mainland Spain is O.K. You can bring back what you like, but Gibralter is a colony of the UK so you have to pay tax on anything over the usual limit from there.
We have just got back from being on the navigator which we have been on twice this year each time from Southampton. the cigs are cheap on the ship £11 for 200, they tell you that you can only take 200 back but everyone takes loads, as we did as well. customs at Southampton not a problem you tend not to see anyone, as one of the workers on the ship said that they don't know of anyone being stopped so go for it. have a lovely cruise the ship is lovely.