This is both treasonous and utterly wrong-headed.
1. The UK operates an adversarial system where one has a right to defend oneself and be judged by a jury of one's peers. This was created for very good reason - Rule of Law. In Sharia, there is no right to speak or present evidence. The "judge" will decide what evidence will be "permitted" and can disregard whatever they feel like. For all its bogus "religious" pretensions, Sharia is Rule by Men, not Rule of Law.
2. Anyone who thinks this will not result in coercion to agree to a Sharia court is naive, a "useful idiot".
3. Anyone who thinks this will not result in calls for any case involving a Muslim or extension to criminal cases is also naive and a "useful idiot".
Now, Sharia as a voluntary arbitration with no force in law is another thing entirely, for that occurs in a multitude of social interactions, not just Sharia. What is now occurring is quite different - a legally enforceable wedge. It is discriminatory, unequal, divisive, Mediaeval and if people want to live that way personally, then it is their funeral, but it is another thing to tarnish what can be described as the best legal system in the world, English Common Law,
by making it recognise a backwards leap.
This is the work of self-loathers, quislings, appeasers. I suspect most Muslim citizens of the UK will be against this too. It is the last thing they need.
The Libertarian Party will kick this nonsense back to where it belongs - a private matter between individuals.