Try here:

http://www.tfl.gov.uk/modalpages/2625.aspx

It has a journey planner

Hope helps and enjoy London!

It depends on whereabouts on Oxford Street you want to go – it’s quite long. Oxford Circus underground station is in the middle – ish. To get there from Victoria, take the Victoria line (light blue).

To get to the London Dungeons you need to get to the London Bridge underground station on the Northern line (black). To get there from Oxford Circus, take the Central line (red) as far as Bank, then either walk across the bridge to the dungeons from there, or change to the Northern line and get off at London Bridge.

For H&M, Top Shop, Niketown, John Lewis, other womens fashion shops and top of Regent Street:
Victoria Line northbound to Oxford Circus.
For Selfridges, Virgin Megastore, M&S, Debenhams, Boots:
Victoira Line northbound to Green Park. Change to Jubilee Line northbound to Bond Street.
London Dungeons: Take the Central Line eastbound from either Bond Street, Oxford Circus or Tottenham Court Road to Bank. Change at Bank to Northern Line southbound to London Bridge. The Dungeons are sign posted from London Bridge station.

TfL journey planner is sometimes complicated in the way it plans. You should have a good day following the instructions above. By the way – use Oyster card for cheaper tube travel.
Have a great day out.

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