My wife has gotten a payraise at her work this year and she's fairly happy about it. However when she received her letter with the new rate, it told her the raise would be effective from middle of October, not the end of the financial year (which has been the case at almost every company she and I have ever worked at); ie, the raise is usually effective from July 1 and backdated/back paid.

Is this the law however, or can an employer say we're going to raise your pay and just start the new rate at any old time? I couldn't find much on the Government websites about it.

Thanks in advance :)