yep, so basically the big rich companies get away with it yet the normal small contractors are stung with it. it also doesnt help that no-one, even HMRC, understand the system
There were two reasons for this carp appearing .
1) The 714 system was being corrupted by the IRA on certain projects like the Channel Tunnel .
2) The government were short of cash and decided to hit the small self employed guys , making them virtually PAYE . AND not to forget the payment up front against money you may or may not earn in coming year based on this years earnings .