The UK isn’t exactly the best place for shopping, particularly if you are an American citizen. Our currency isn’t worth much there, so effectively everything costs twice the price. However there are some things worth splurging for to bring home, particularly fine teas and English biscuits.
A sampling of some of the items I purchased in England. Here we have some fine teas purchased from Harrods, along with some marmalade and “regular” teas from Sainsbury’s, a British supermarket chain. Even the “regular” supermarket stuff is superior to what we get at most supermarkets in the states, and its totally worth stocking up.
A view of our new British tea collection placed on the shelf. I managed to pick up some really good Fortnum & Mason and some special edition Twinings teas at the big duty-free shop at Heathrow, along with a selection of nice biscuits as well.
Jaffa Cakes, not to be confused with the slave warrior race from Stargate SG-1. They are a British original and a favorite munchie of the Beatles.
Whoa! 195 calories PER Jaffa Cake!
Jaffa Cakes have a layer of chocolate on the top.
With a layer of jellied orange marmalade in the middle and a yellow cake layer on the bottom. They are addictive as hell, and I’m really pissed I only bought one package of them.
Off The Broiler 
I’m pretty sure that you can find Jaffa Cakes at Fairway.
Actually it says 45 kcal per cake if you read closer :) Which again equals 195 kj (kilo joule). So then you can eat your Jaffas with a little less guilt, maybe…?
No Hobnobs? The king of the Biscuit world!!
You might be able to find Jaffa cakes in the “British Foods” section of some supermarkets. Lu Pims cookies come pretty close, and I can find them in the cookie aisle of all my local shops. You can also buy them (and lots of other British stuff) at http://www.britishdelights.com/.
There are a lot of non-Jaffa(tm) jaffa cakes around. Try these:
http://www.amazon.com/Lu-Pims-Orange-5-29-oz/dp/B0005ZZ3SO/
Also good are these Polish ones:
http://polartcenter.com/Delicje_Chocolate_Champagne_Biscuits_p/9700465.htm
John K is right: Hobnobs are a must.
I could never get into Jaffa cakes…