If you do not operate a payroll, then this does not apply to you.
For those that do run a payroll, even if there is only one employee, then the new changes will apply from 6th April 2013.
In the past it was possible to manually run a payroll, filling in the forms by hand and submitting these to HMRC when required during the year.
Now, this will be replaced by a submission to HMRC whenever someone is paid and any tax due to HMRC may also become payable earlier rather than under the old quarterly payment schedule.
Due to the additional requirements, particularly potential fines when the person running the payroll is on holiday, many people have decided it is simpler to outsource their payroll preparation to a bureau.
If you would like a referral to a payroll bureau who can assist you, please do contact me for an introduction.