Parliament sits above the courts as effectively the Supreme Court of the UK, where everybody's interests are notionally represented (the current mis-named 'supreme court' is really just the Court of the United Kingdom). The King, via the Ministers of the Crown, could propose a building as a Bill in Parliament. If Parliament then passes that as an Act, then it will happen and nothing can stop it from happening. Including using the Army to detain and remove protestors if necessary. All it needs is the relevant sections in the Act.
Recovering this power is why Brexit was so important. With it we can build the green infrastructure we need as we built the railways - via dictatorial Acts of Parliament that brook no opposition.
Now all we need are MPs prepared to use that power to save us from oblivion.