Expanding on this theme, Ronan Lavery - who is challenging the government on behalf of Northern Ireland campaigners - says the constitutional settlement in Northern Ireland is delicate and multi-layered and the UK's departure from the EU could have a seismic effect on it. 

Image source, Supreme Court

Ronan Lavery is now addressing the court. He says life in Northern Ireland is "complex" and far from the binary state of affairs suggested in some legal judgements. The patchwork of religious, political and historical associations that many of its residents are boundy by is exemplified by his client Raymond McCord, the lawyer tells the court.

House of Commons
Parliament

Prominent Leave campaigner and former secretary of state Michael Gove says that it is important to involve the 48% of people who voted Remain in the referendum. 

He says he is disappointed in Sir Keir Starmer's speech, which he cites as being "longer than many Pinter plays and Haydn symphonies"; criticising it for not revealing what Labour's position is on a future relationship with the European Union. 

Mr Gove says the speech was "40 minutes of pious vapouring; a hole in the air masquerading as an argument". 

Despite attempts to "complicate and obfuscate" the matter, Mr Gove says that it was "entirely clear" what people voted for in the referendum, saying that the public were fully informed - mostly by the Remain campaign of what would happen if the UK left the EU. 

The MP for Surrey Heath says that those who opposed the UK leaving the EU need to promote views of how to take the country forward, instead of "looking back in anger remorse and regret". 

House of Commons
Parliament

Sir Bill Cash, chair of the EU Scrutiny Committee, tells MPs "we should say no to the single market, no to the customs union", because we "cannot be subject" to European laws and regulations. 

The prominent Eurosceptic reveals to the House he voted 'yes' in the 1975 referendum on the UK's continued membership of the European Economic Community. 

He tells MPs that it was when only that he became an MP and a member of a committee focused on European legislation that he "began to see the truth". 

"Yes to regaining a democracy which this House has stood for hundreds of years," he concludes.

Image source, Supreme Court

David Scoffield, who is representing Northern Ireland claimants against the government, says ministers are being “cavalier” over how triggering Article 50 would affect its devolution settlement.

The 1998 Belfast Agreement, better known as the Good Friday Agreement, "makes clear that all the arrangements hang together", he says, while the "machinery and architecture" of the devolution settlement set out in the 1998 Northern Ireland Act would clearly be affected by EU exit.

The main flaw in the government's argument, he argues, is that the North-South ministerial council is required to implement policies - including those deriving from EU membership - on both sides of the border.

House of Commons
Parliament

Former Labour party leader Ed Miliband tells the House this debate is not just about whether you were for Leave or Remain, it is about the need to both unify a "deeply divided country" and "honouring the result" of the referendum.

Mr Miliband argues a plan "must be produced in January", so that there is enough time for Parliament and the British people to properly debate the proposals. 

The government will be stronger and have a "mandate" for their proposals if they are brought to Parliament, he remarks.

Image source, Supreme Court

It is now the turn of David Scoffield QC to take the floor. 

He is representing Steven Agnew, a member of the Green Party of Northern Ireland, and other NI campaigners who are contesting the government's right to trigger Article 50 without the say-so of Parliament.

Addressing the argument made by the government yesterday that the devolved administrations have no competence in foreign affairs, he says this is a "very broad-brush" interpretation of existing statutes with regard to Northern Ireland, Scotland and Wales and, in his opinion, not a "correct starting point". 

Winding up his argument in the Supreme Court Dominic Chambers - who wants last month's High Court ruling to be upheld and the government's case dismissed - accepts there is a difference between "political and legal sovereignty" and says it is important that the public feel they have power within the constitution.

But he says the fact of the matter is that the public have a "political power" to elect MPs and it is MPs themselves who make the law. 

Lib Dem leader Tim Farron has been meeting the European Parliament's lead negotiator, Guy Verhofstadt, in Brussels.

Mr Farron said MEPs would have to sign off on any deal over the UK's exit from the EU.

And on the mechanism for beginning formal negotiations, which Theresa May has promised to invoke by the end of March, he added:

The Lib Dems are calling for a second referendum on the terms of the Brexit deal that is reached after the negotiations.

House of Commons
Parliament

Conservative veteran Ken Clarke tells an enraptured House that having scrutiny in such a level of policy-making and debate is "not a threat" to government, or the "quality of decisions".

Urging greater clarity within the debate, Ken Clarke says the choices which are "now being struggled with", such as membership of the customs union, "are a mystery to 99%" of the people who voted in the referendum". 

Dominic Chambers, who is challenging the government, concedes that although lawyers may appreciate the varying legal force of a bill rather than a Commons resolution or a motion, it might be lost "on the man on the Clapham omnibus" - that's not a phrase we've heard that much recently. 

Image source, Supreme Court

Dominic Chambers finds himself suddenly under a certain amount of pressure with Lord Mance, Lord Kerr, Lord Sumption and Lord Reid all weighing in on the issue of what the lawyer believes Parliament needs to do to authorise Article 50. 

Lord Mance questions whether the House of Commons briefing cited earlier by the lawyer is admissible while Lord Carnwath ponders whether the court has the right to tell Parliament how to exercise its sovereignty.

He questions whether Mr Chambers believes a simple parliamentary motion is not enough, that is effectively asking Parliament to pass a one-line bill authorising Article 50 wave a "magic wand that changes everything". 

Lord Kerr said the justices should not be issuing "an edict to Parliament or the executive saying you must do this and must do that". 

In response, Mr Chambers says his argument is that, in this instance, the Supreme Court is the "guardian of parliamentary sovereignty" but Lord Neuberger, the president of the Court, seeks further clarification about the legal weight of a bill as opposed to a parliamentary motion.

House of Commons
Parliament

Chair of the Exiting the EU committee, Hilary Benn, begins by expressing concern about the "continuing tone" surrounding the debate.

Mr Benn calls for an end to people being labelled "democracy deniers". 

He says the result of the referendum has been accepted and "Parliament will vote in favour of triggering Article 50". 

The government should work to "unite" all those living in the United Kingdom around the forthcoming negotiations and recognise its responsibilities to the "48% as well as the 52%". 

To the secretary of state, Mr Benn asks for assurances that "there will be a vote" in Parliament. 

In the Supreme Court Dominic Chambers quotes from a House of Commons Library briefing paper to support his argument that the referendum was advisory and not binding on Parliament. 

He remarks that the government's lawyers spent a lot of time trying to make a distinction about whether the referendum was advisory to government or Parliament but he says this is "not to the point".

The only issue is whether June's vote had a "legal effect".

House of Commons
Parliament

Conservative MP Iain Duncan Smith says the Opposition have failed to define what "leaving" the European Union is. This "speaks more about their own problems" rather than any issues facing the government, he says.

In support of the government amendment, Mr Duncan Smith, who campaigned for Leave, argues that leaving means that we are "no longer subject to European law", and everything else will "flow" from this.  

Mr Duncan Smith says: "I would rather we stayed in the EU, than stayed in the customs union."

Read more about the customs union here.

Image source, Getty Images

Dominic Chambers is addressing the issue of whether the referendum earlier this year was advisory or binding.

He quotes what Edward Short, the former Labour cabinet minister, said back in 1975 ahead of that year's referendum on remaining in the EEC.

He says Mr Short - who was leader of the House of Commons under Harold Wilson at the time and died in 2012 - told MPs the referendum was entirely consistent with parliamentary sovereignty and while government was "bound by its result, Parliament cannot be bound". 

House of Commons
Parliament

SNP Europe Spokesperson, Stephen Gethins, rises to make his party's contribution to the debate. He says the government proposals "are not enough" and that "a significant number of questions remain unanswered". 

Arguing for Scotland to be given powers over free movement of people, Mr Gethins reminds the House of the comments Michael Gove made in the pre-referendum debate - that it would be "for Scotland to decide" on immigration numbers to the country after Brexit.

Mr Gove nods from across the chamber and the SNP benches erupt in cheers. 

"Freedom of movement is something that we all benefit from," Mr Gethins adds.

House of Commons
Parliament

David Davis says the government has been "as clear as is sensible at this stage" on the issue of future trade and customs arrangements with the EU; saying that the UK is seeking the freest possible trading arrangements. 

He says that the best deal is most likely to be achieved by a negotiated outcome, which has a "range of means" to arrive at a deal and a range of possible outcomes. 

"It does not make sense to box ourselves in at this stage," he says. 

Mr Davis says he wants the UK to be a "global, outlooking nation" that embraces the opportunities of Brexit whilst maintaining best possible relationship with the EU.