BACS is an easy way of transferring money electronically from one financial institution to another. A BACS transaction takes between three and five working days to complete and the BACS system is used by most Umbrella Companies. If an Umbrella Company pays you by BACS on a Friday, the money will usually take three working days to reach your bank account (i.e the following Tuesday).
CHAPS is short for Clearing House Automated Payment System. This is a same day transfer of money from one financial institution to another. There is usually a charge for the CHAPS service so it is likely that an Umbrella Company or ASP will pass this charge onto you.