We produce a ticket with Pen Reactive Security print on the reverse,

Using a special felt tip pen, when you rub this over the reverse of the ticket the words VOID appear. The advantage of this method is what you cannot see you cannot copy.

For an additional 2p per Horizontal ticket + the cost of a Reactor Pen @ £3.85 + VAT you can have peace of mind knowing that your ticket cannot be copied or show up under a UV lamp.