Mastercard is offering a printable voucher which enables cardholders to receive 2-for-1 entry to UK theme parks. The vouchers are valid at Alton Towers, Chessington World of Adventures, Thorpe Park, and Legoland Windsor along with a number of other UK attractions operated by Merlin Entertainments Group.

A book out of 8 vouchers can be downloaded from Mastercard's website. The voucher can then be redeemed when buying a full price adult ticket, which must be purchased with a Mastercard.

A single adult ticket bought on the gate costs £38 at Alton Towers. With two online adult tickets costing £60.80, there is a potential saving of over £22 from taking advantage of the offer at the park.

The vouchers are valid through most of the 2010 season, but there are some block-out dates on which they can't be used:

• Alton Towers - Valid until October 31, 2010. Block-out dates: May 23, June 26, July 5-9, July 12-16, July 19-20, 2010.
• Thorpe Park - Valid until November 7, 2010. Block-out dates: July 12-16, July 19-31, October 29-31, 2010.
• Chessington World of Adventures - Valid until November 1, 2010. Block-out dates: all Zoo Days
• Legoland Windsor - Valid until November 7, 2010. Block-out dates: August 1-31, 2010 (note that the park is closed on some days during the season).

For non-Mastercard holders there are a number of alternative ways to get a similar discount at Merlin's UK theme parks during the 2010 season. These include 2-for-1 vouchers from WHSmith stores (which are available until April 11), and 50% off vouchers from Burger King (which are available until October 31).