It's important to remember that many recent employment law cases ruled on employment law. There's no requirement for HMRC to follow these findings for tax purposes but you expect they'll be reviewing their position.
Along similar lines, there have been some recent HMRC 'IR35 status' tribunal cases where (usually) one-person limited companies have had mixed success as to whether they are an employee of their clients.
The detail behind today's speech offered a lot of new consultations and delayed implementation dates to beyond 2019, which seems to me a 'wait and see' how the Brexit negotiations go before finalising a lot of changes.
The speech itself ended with a grand finale announcing the abolition of stamp duty for first time buyers of residential property purchases up to £300k.
The Chancellor's humour today peppered around some dry, but important, statistics won't prevent today's headline being all about the self employed Class 4 national insurance increase from 9% to 10% in April 2018 and 11% from April 2019.