The Society of West End Theatre, the delightfully named SWET, wisely renamed itself Society of West End Theatre some years ago.
They have for some years offered discounted tickets for the off-peak period for theatres. Given the depths of the UK recession (Are we still in our double-dip or have we progressed to the third-dip?), this probably a wise move and it offers the visitor a chance to see excellent theatre at a discounte price. Most of the offers seem to run until mid-February 2013.
Seats are £10, £15, £25 or £35, depending on the show and where you would like to sit. (Some bookings attract a small fee).
Shows include Musicals, Plays, Dance and Opera as well as family shows.
The system works on an allocation basis so you may not get the same seat as if you had called the theatre directly.
More information via this link.
Some examples to illustrate the savings:
12 January 2013, 2:30pm Matinee.
Normal price £62.50, reduced to £35.
I was offered Row ZB (back third), seat 17. Not a bad seat at all at half price. (Stage at the bottom)
13 February 2013, 2:30pm Matinee
Normal price £50, reduced to £35.
I was offered Row A (three rows back), seat 8, dead centre.