A one-day London route built around Westminster, the river, a museum choice, and an evening neighborhood.

Start at Westminster Abbey, Parliament Square, and the river, then walk through St James’s Park toward Buckingham Palace for a classic first London hour.
Choose the British Museum, the National Gallery, or the Tower of London as your single big interior. Do not try to stack more than one into a one-day plan.
End along the South Bank with river views, the London Eye, and easy dinner options — a relaxed close with good light over the Thames.