They must be completed and submitted with HM Revenue and Customs by 31st July 2009.

This can be done either by returning the Annual Review notice to HM Revenue and Customs or by calling the Tax Credit Helpline on 0845 300 3900.

It is being superseded by the new A4 version which was first introduced in October last year.

The new P45 includes details of the employee’s date of birth and their gender.

HM Revenue and Customs (HMRC) said that any back stock of the A5 P45s should be destroyed by 6 April and that employers must use the larger format instead.