Is there a UK equivalent to Walmart

Walmart is called ASDA in the UK. Not sure where you're going in England but the one nearest to London is in Hounslow west (near Heathrow) near the tube stop of the same name on the Piccadilly line heading towards London. A "chemist" (drug store) would be much easier to find and get to.

Boots and Superdrug are the 2 biggest "chemists" in the UK. They are pharmacies like Rite Aid, CVS, etc. They are on every corner and near most tube stations and high streets. Boots has a great Boots line of toiletries that is very cheap (1 pound ($1.60) for a bottle of shampoo, Shower gel, etc) and high quality for the store brand, plus they also carry most american brands. It's so good that when I come back through Heathrow, I always stock up on them after security at Boots in the airport.

Full sized Grocers (Tesco, Sainsburys, Somerfields) have toiletries but are hard to find in the city. They do have Express versions of the stores but they are usually limited to food items.

oh i hope not...

Yes, everything you are looking for will be in British supermarkets. As mentioned above Asda in the UK is owned by Wal-Mart. Other major supermarket chains include Tesco and Sainsbury. Chemist chains like Boots and Superdrug will have toiletries, as will many small independent chemist shops if you are in a city centre with few supermarkets.

There are also stores called Poundland (everything's a £) and the 99p store, they both sell all bathroom goods (and lots of other stuff too).

Doesn't M&S have that kind of stuff, maybe a bit more, but they seem to be everywhere in the centers? Maybe more convenient.

When I am in London, I cant throw a shoe without hitting a Superdrug or Boots.

Another couple of shops to keep an eye out for are Savers and Wilkinsons which both sell brand-name toiletries very cheaply. You'd have to be fantastically unlucky to find yourself anywhere that doesn't have a shop that sells cheap toiletries!

Anything you would need you could find at Boots.

Thanks for all the suggestions.