It basically prevents one person "contractor" companies from acting like employees but getting paid like a business and so somehow avoiding tax. If the HMRC thinks your contract with BigCo means you are a "disguised employee" then they will ask you for your missed back taxes.
But on April 2020 they will stop asking me for my back taxes and will instead ask the client for whom I work (ie BigCo). As such BigCos across the UK are unwilling to face years of potential back taxes and will from April 2020 do some combination of
- state every freelancer / contractor working for them is really a disguised employee so that the employee's company must pay the equivalent income tax / NI
- let go of their contractors en mass
- push their contractors to major suppliers like Accenture
- move their UK based work off shore to NYC / Paris / Mumbai
Basically combined with Brexit, UK tech jobs are going to disappear / take a 25% haircut or go abroad.
