(See Comment on: IR35 guidance 'as clear as mud')
HMRC could (will?) now start IR35 investigations by asking you to justify your IR35 position. This means all the work is on your end, rather than defending specific points that HMRC might first raise.
So if you are in business, you had better have legal advice available right from the start of any contact from HMRC now. Great business for the legal advice industry, not so great for the contractor community. This whole IR35 Forum process just gets worse and worse the more we hear.