This timeline shows the different points in time where a change occurred. The dates will coincide with the earliest date on which the change (e.g an insertion, a repeal or a substitution) that was applied came into force. The first date in the timeline will usually be the earliest date when the provision came into force. In some cases the first date is 01/02/1991 (or for Northern Ireland legislation 01/01/2006). This date is our basedate. No versions before this date are available. For further information see the Editorial Practice Guide and Glossary under Help.