If you are talking about the London Pass it is widelly considered a rip-off, especially the transit passes.

Check out www.daysoutguide.co.uk for better deals like 2for1s when you buy a train (NOT Oyster) tickets for transit.

Many of the important public galleries and museums are free. A lot of the commercial attractions covered by passes are just that: all a matter of taste as to whether they appeal to you and whether you'd get your money's worth. Unfortunately, there's no short-cut alternative to sitting down and working out what you want to see and how much it's likely to cost you without such a pass before you decide whether or not one would be of any value to you.

Bear in mind that most visitors will only need public transport for zones 1 and 2 - as I understand it, the London Pass covers all zones, which means you're paying for a lot more than you'd ever use.

As Patrick says "Many of the important public galleries and museums are free" what a great pass system.

Let's see. You can visit the following for the sum total of ZERO admission costs.

British Museum
British Library
Tate Britain
Tate Modern
National Gallery
National Portrait Gallery
V&A
Science Museum
Natural History Museum
Imperial War Museum
National Maritime Museum
Museum of London

So why again would you need a pass that costs a lot of money just so you can visit tertiary sites for "free"?

Do what jamikins says. "Train tickets" include a 7-day Travelcard for London transport that you purchase at a National Rail station (Waterloo, Charing X, Paddington, etc.). Go to daysoutguide.co.uk, print as many vouchers as you want before you leave. Save 50% of cost of admission (if there's 2 of you) on the Tower, Cabinet War Rooms, Hampton Court Palace and more.

St Pauls is even included in the 2for1s right now!

Thank you very much! Great advice.