Going the first weekend in March for 4 days. Do we really need to buy our tickets online beforehand. The plan is to go to Tower of London, St Pauls and Westminster Abbey on a Saturday. I was planning on buying the Tower of London but "winging it' for the others. Suggestions for tea after Westminster Abbey? On Sunday we planned on going to Churchill War Room after the changing of the Guard, and St James park. Should we prebuy for the war room and suggestions for lunch? We do have dinner reservations for Blacklock.

Monday is open.

Should we see Kennsington Palace on our first day or skip it and go to Albert and Victoria instead.
appreciate any advice.

OK -- are you trying to do the Tower of London, St Paul's Cathedral AND Westminster Abbey all on the same day?? That is a a LOT. 3+ hours at the Tower, minimum of 90 minutes at St Paul's and a good deal longer if you climb to the Whispering Gallery and/or Dome and explore the Crypt. Then another 90 mins to 2 hours at the Abbey -- plus criss crossing all of central London twice and squeezing in lunch. London is enormous and while the public transit is great -- it still takes quite a bit of time getting from place to place so far apart. A good rule of thumb is plan on one major site in the morning and one major site in the afternoon and maybe fitting in one other sort of second tier site sometime during the day.

Major sites would include among others - the Tower, V&A (Notice it is the Victoria and Albert not Albert and Victoria) Westminster Abbey, British Museum, National Gallery, St Paul's, Churchill's Cabinet War Rooms, Tate Modern, and several more. Sites taking not quite as much time would be Kensington Palace, some of the smaller art galleries (Wallace Collection, Courtauld) maybe Tate Britain. The National Portrait Gallery could fit in either category depending on your interests.

If you still plan on hitting the Tower, St Paul's and the Abbey on the same day you 100% will need to pre-book all three tickets to get specific times.

If you are flying in long haul I would not do either the V&A or Kens Palace that day -- what with jet lag and such, heavy duty sight seeing should wait til day 2. IMO/IME The V&A is a MUST -- Kens Palace is a Maybe if there's time.

If you only have four days in London I personally would not waste any time at the Changing of the Guard -- it is a real time waster -- eats up from about 9 AM (especially on a Sunday when the crowds are enormous) til well after noon.

If it was me -- I' try to do the Abbey and War Rooms on he same day since they are short walk apart. Morning in the Abbey, lunch in the cafe, afternoon at the War Rooms . . . not on Sundays obviously since there is no touring the Abbey on Sundays.

what janisj says +1