Campaigners have said Britain now risks a collapse in confidence in our political system, and have called for wide-ranging changes to Britain's constitution following the Article 50 ruling.

Campaign group Republic has said that the ruling highlights need to clarify the powers of the government, parliament and people - in a new written constitution.

Graham Smith, the group's CEO, said today:

"We now face a serious risk of a collapse of confidence in our political system.  We need to re-invent Britain's parliamentary democracy, re-balancing power between the citizen, parliament and government."

"The lack of clarity about the power of a referendum, a lack of public understanding about the role of parliament and the excessive powers of the government have all conspired to leave us on a constitutional precipice."

"This is why a written constitution is needed - the people have a right to know how we govern ourselves, who has what power and how they can be properly held to account."

"Parliament should be at the centre of that constitution, fully elected and properly accountable.  And parliament needs more independence from the government."

"And we need an end to the royal prerogative and clarity over the powers the government has.  We need clear rules about who can trigger a referendum and on what issues."

Republic calls for a written constitution, a fully elected parliament, a re-balancing of power between MPs and government and an elected head of state who can guard and referee the system.