Customs and Duties
You're always allowed to bring goods of a certain value back home without having to pay any duty or import tax. But there's a limit on the amount of tobacco and liquor you can bring back duty-free, and some countries have separate limits for perfumes; for exact figures, check with your customs department. The values of so-called "duty-free" goods are included in these amounts. When you shop abroad, save all your receipts, as customs inspectors may ask to see them as well as the items you purchased. If the total value of your goods is more than the duty-free limit, you'll have to pay a tax (most often a flat percentage) on the value of everything beyond that limit.
There are currently two levels of duty-free allowance for entering Britain: one for goods bought outside the European Union (EU) and the other for goods bought within the EU.
Of goods bought outside the EU you may import the following duty-free: 200 cigarettes or 100 cigarillos or 50 cigars or 250 grams of tobacco; 4 liters of still wine and 16 liters of beer and, in addition, either 1 liter of alcohol over 22% by volume (most spirits), or 2 liters of alcohol under 22% by volume (fortified or sparkling wine or liqueurs).
Of goods bought within the EU, you should not exceed the following (unless you can prove they are for personal use): 800 cigarettes, 400 cigarillos, 200 cigars, or 1 kilo of tobacco, plus 10 liters of spirits, 20 liters of fortified wine such as port or sherry, 90 liters of wine, or 110 liters of beer.
Pets (dogs and cats) can be brought into the United Kingdom from the United States without six months' quarantine, provided that the animal meets all the PETS (Pet Travel Scheme) requirements, including microchipping and vaccination. Other pets have to undergo a lengthy quarantine, and penalties for breaking this law are severe and strictly enforced.
Fresh meats, vegetables, plants, and dairy products may be imported from within the EU. Controlled drugs, switchblades (aka flick knives), obscene material, counterfeit or pirated goods, and self-defense sprays may not be brought into the United Kingdom; firearms (both real and imitation) and ammunition, as well as souvenirs made from endangered plants or animals, are barred except with relevant permits.