Dan wrote:
where is the best place to park when going into london for the day on the
tube.
I will be coming from the M1

It's not on the tube, but you could consider using Luton Airport
Parkway, where there's a large car park and frequent Thameslink and
Midland Mainline services to London St. Pancras.

http://www.thameslink.co.uk/plan_you...tml?1068575778
http://www.midlandmainline.com/Displ...p?StationID=20

--
Mark Etherington