Backdating ESA

Does anyone know if ESA can be backdated after the initial award?
I think it can be backdated for three months - but does it have to be done on the initial application?

Thanks

It can be backdated but only 3 months from the date of the application for backdating, which is in effect a separate claim for the earlier period and thus subject to the usual 3 month backdating limit. This means there is no point in applying for backdating once the award has been in payment for three months.