An Horizon label is an adhesive postage label that is a type of variable value stamp. The labels were introduced in the United Kingdom in 2002 as part of the computerisation of the counter services of the post office network of Royal Mail using the Horizon System. The first labels were large plain labels composed purely of text but later labels are of a gold colour with a Machin head and a repeating pattern of the words ROYALMAIL in order to prevent forgery. The training of postal workers includes the use of voided horizon labels, noted as early as 2003.