Noel Young Wines
Top notch Cambridge-based operation with a huge, interesting and eclectic list. Good prices. I've ordered from them before and received excellent service.

Bibendum
Until last year they had a shop in Primrose Hill which used to be a nice lunchtime walk through Regent's Park from my Central London workplace, but this has now been closed. Excellent fine wine range; slightly less interesting 'normal' range mostly consisting of the wines that they are agents for in the UK. Manages to combine the best of the old-style merchants with a more modern business approach. 

Berry Bros & Rudd
Ultratraditional St James' St shop has to be seen to be believed: it is like a museum! Berry Bros is an institution. Surprisingly for such an old fashioned merchant, they have a pioneering online sales site. Prices on the high side.

Justerini & Brooks
Another ultratraditional St James' St merchant. You are greeted by polite young chaps in pinstripe suits with impeccable accents who thrust a list into your hands, from which you can order -- most of the stock is not held in the shop but must be delivered the next day from the warehouse. Good list and mostly reasonable prices.

Fortnum & Mason
Wonderful department store on Picadilly, which has a lovely warm, traditional feel to it. Excellent although slightly limited selection at fair prices: you'll find things here that are difficult to obtain elsewhere. Helpful staff. Strong on Western Australia, for some reason.

Harrods
As you might expect, very strong on the classic regions. Impressive array of famous names, with a few hidden gems tucked away. Prices are high, but you won't be coming here for £7 Australian wines! It's a fun place to shop.

Selfridges
Rather refined atmosphere, and the staff can come across a little snooty, but excellent, thorough range. Pricey though.

Bentalls
An excellent, imaginative range, particularly strong on Portuguese wines. Staff are very helpful, and the store lacks that rather discouraging snootiness that some of its central London counterparts possess.

Oddbins
The leader of the pack, with a dynamic approach, informed staff, keen prices and a pretty strong range. I spend a lot of time in Oddbins! Especially good are their Fine wine stores, which enable them to buy smaller parcels of interesting wines, which they then sell at very fair prices.

First Quench (Bottoms Up/ Thresher/ Wine Rack/ Victoria Wine)
The range is comprehensive in the bigger stores, but even the smaller Thresher branches can still boast some interesting tipples. Staff generally lack knowledge (after all, they are paid close to the minimum wage), so don't ask for advice. Some interesting finds here, amid the usual branded and high production items.

Fullers
Brilliant range of wines from this small London chain, based around the Fullers brewery in Chiswick. Buyer Roger Higgs has unearthed some gems, and staff training seems to be given a priority, so it is usually worth asking for tips.

Nicolas
The French seem to have a more generous view of profit margins than the British. Expect to pay well over the odds for dodgy vintages at this unimpressive range of shops, usually located in wealthy areas where people aren't going to realise (or care, perhaps) that they are being fleeced!

Specialising at the cheaper end of the market, supermarkets now sell more wine in the UK than any other form of retail outlet. It often strikes me that the variety of wines offered by even a moderate sized store must confuse the life out of the average shopper. Amid the many dozens of inexpensive, bland wines that cram their shelves, all the retailers here offer some surprising gems in their ranges, especially in the larger branches which carry a bigger list. Don't expect any sensible buying advice, although you may strike lucky in larger stores.

Tesco
Probably the best of the supermarkets, with some adventurous buying, particularly each May when a wine festival is held and the range bulges with some smaller parcels of hard-to-get wines. Especially strong on Australia.

Sainsbury
Comes a close second to Tesco. Large, generally relaible if not excing range that is pretty consistent across the board.

Waitrose
Some gems to be found here, but not as broad a range as Tesco or Sainsbury. Nice high end selections.

Still developing in the UK: many merchants now have websites, but there are relatively few dedicated online merchants from whom you can order wine directly from your browser. I aim to review these services in the near future.