Category Sandwich Shops
Don't go to Pret a Manger or Subway!. Instead go to a local sandwich shop and get them to make one for you freshly. There are good ones on [Charlotte Street]?, just off Oxford Street. And also a fantastic one on [Battersea Square]? which is nowhere near Oxford Street but I'll mention it anyway. Remember Kiddies, beware branding, it's usually hiding something. Fight homogenisation, go to a deli. MMmmkay. Camden Market on a saturday is worth a visit for local produce and fresh lunch / sandwich ideas.
There are lots of independent sandwich shops between [Gray's Inn Road]? and [Lamb's Conduit Street]?, where you can buy fresh sandwiches with a more interesting variety of fillings than any chain could offer, and usually for less money too. (For example, Food Bazaar, Goodfellas, Konditor and Cook.)
Of the chains out there there are some good ones, specifically, Benjy's and O'Briens Irish Sandwich Bar who taste *SO* much better than Subway. Subway, of course, are identical the world over, and offer nothing particularly interesting to the gourmet of sandwiches, barring of course the gorgeous Subway Melt which is ace, especially with jalapeno peppers. (YMMV.) - Earle
Cafe Fresco, W1T 2HG, just next to Goodge Street Station, does a very nice toasted BLT ciabatta (without mayonnaise). Peruginos, just around the corner, also do good sandwiches and sit-down meals. --Rjp
For a more expensive chain, Benugo have a number of branches in London, some of which offer free wireless.