The final phase of the Big Number campaign has now been completed. The changes went smoothly as old mobile, pager, special rate and premium rate codes were switched off.

The new numbers had worked alongside the old ones for over 18 months. This safety net ended on 28 April when old codes were switched off overnight.

Four million old numbers still in use were switched off. All mobile and pager numbers not beginning 07 were changed. In addition, all special rate numbers now begin 08 and all premium numbers 09.

Research by the Big Number released the week before the switch-off showed that, while two-thirds of people were aware of the changes to mobile phone numbers, most people did not realise that the changes were not a simple matter of adding a '7' to existing codes.

However, by 11am 72% of callers were using the correct numbers meaning that only 2% of all calls made to mobiles were failing to get through. The proportion of callers using the correct numbers at the same time following changes to London codes and numbers was only 65%.

The new UK numbering scheme is now in place and fully operational. Nine billion telephone numbers are available and the new codes mean consumers can clearly see what type of service they are calling and the likely cost of the phone call.

For further information please contact the Big Number helpline on 0808 22 4 2000 or see the Big Number website at www.numberchange.org.