The people voted 'out'. The High Court ruled that MPs must endorse before the process can begin. The Government want to start the process without delay so they've appealed the ruling to the Supreme Court.
My view is that the Supreme Court will agree with the High Court decision but will clarify that it will not be necessary to go through the lengthy procedure normally required for an Act of Parliament. They will say that it was not clear whether the Referendum was granted by Parliament as 'advisory' or 'executive/ binding'. Therefore MPs need to vote on a simple issue. Did they intend the referendum to be binding on Government? If a majority vote 'Yes', then the Brexit process can be triggered.
If I'm right, Brexit hasn't been derailed.