Just 200.
Quotes from the HMRC website:
"Though the whole of Cyprus is part of the EU, goods from any area of Cyprus not under effective control of the Government of the Republic of Cyprus are treated as non-EU imports"
Source:
http://customs.hmrc.gov.uk/channelsPortalWebAp p/channelsPortalWebApp.portal?_nfpb=true&_ pageLabel=pageTravel_ShowContent&id=HMCE_P ROD_010221&propertyType=document#P10_662
"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"
Source:
http://customs.hmrc.gov.uk/channelsPortalWebAp p/channelsPortalWebApp.portal?_nfpb=true&_ pageLabel=pageTravel_ShowContent&id=HMCE_P ROD_010220&propertyType=document
Chris