Instructions:"American Express Cardmembers who are shopping online at Ocado for the first time will receive £15 off an order of £90 or more.
To take advantage of this offer, simply place an order before 31 August 2008 and enter VOU1865283 when you check out at
Simply visit Ocado.com to place your first order."
Although it says American Express Cardholders - I'm not sure where you'd have to prove this so give the voucher code a go and see what happens!!