This is very significant.
The High Court in Britain has ruled that only Parliament has the power to trigger Brexit by notifying Brussels on the UK's intention to leave the European Union.
Prime Minister Theresa May had insisted that the government alone had the authority to put Article 50 into motion but, in a massive blow to her authority, lord chief justice Lord Thomas of Cwmgiedd has ruled that all MPs must push Brexit through.
This would mean that Brexit will be a far more drawn out process than had originally been envisaged.
Lord Thomas said, “the most fundamental rule of the UK constitution is that parliament is sovereign."
It is likely that the decision will be appealed to the Supreme Court, with space cleared in judges' schedules for an appeal early next month.
May had said she would activate Article 50, formally notifying the EU of the Britain's intention to leave, by the end of March 2017.
This follows the UK's decision to back Brexit in June's referendum by a margin of 51.9% to 48.1%.
