Prime Minister pledges to trigger Brexit by end of March 2017
Theresa May has vowed to trigger Brexit by the end of March 2017 even if the UK's highest court decides parliamentary approval is required.
The Prime Minister said the Government will "respect" the verdict of the independent judiciary, with the Supreme Court to announce its decision "as quickly as possible" in the new year.
Labour leader Jeremy Corbyn called on Mrs May to make sure her new year's resolution includes a "commitment to build better relations" with the UK's European partners to ensure she can secure the best deal possible.
The Supreme Court legal challenge from the Government e merged after a panel of three High Court judges decided in November that Mrs May lacked legal power to use the royal prerogative to trigger Article 50 of the Lisbon Treaty to start the two-year process of EU withdrawal.
Mrs May, updating MPs on last week's European Council meeting, said: "I'm clear the Government will respect the verdict of our independent judiciary.
"But I'm equally clear that whichever way the judgment goes we will meet the timetable I have set out.
"At the council I also reaffirmed my commitment to a smooth and orderly exit, and in this spirit I made it clear to the other EU leaders that it remains my objective to give reassurance early on in the negotiations to EU citizens living in the UK and UK citizens living in EU countries that their right to stay where they have made their homes will be protected by our withdrawal."
Mr Corbyn said Mrs May and the UK are becoming "increasingly isolated" on the international stage.
He said: "As we move swiftly towards the triggering of Article 50, I want to appeal to the Prime Minister to not only work hard to heal those divisions in Britain but also to make sure her new year's resolution includes a commitment to build better relations with our European partners, so we get the best deal for the people of this country - not just a Brexit which benefits business and bankers.
"At the moment it's clear on the international stage the Prime Minister and Britain are becoming increasingly isolated."
The Opposition leader said his talks with European leaders have shown they are becoming "increasingly frustrated" by Mrs May's "shambolic Government and the contradictory approach" to Brexit negotiations.
He told the PM: "The mixed messages from your frontbench only add to the confusion. This Government fails to speak for the whole country.
"Instead we hear a babble of voices speaking for themselves and their vested interests."
Mr Corbyn raised contradictory statements from officials and ministers linked to the length of time needed to secure a Brexit deal and whether there will be transitional arrangements.
He added: "The people of Britain deserve better than this confusion at the heart of Government."
Mr Corbyn also claimed "confidence is being lost" as he pointed to Office for Budget Responsibility forecasts for 2017, noting growth, wages and business investment have been revised down.
Mr Corbyn asked Mrs May to give the UK "real answers", including when MPs will receive the Government's Article 50 plans and how long the process of withdrawal will take.
He also questioned if the UK will have to pay 50 billion euros to honour EU budget commitments until 2020.
On EU citizens in the UK, Mr Corbyn asked the Government to "end the worry and uncertainty" by guaranteeing their rights before Article 50 is triggered.
Mrs May, in her reply, reiterated the UK will not get the best possible deal if it states everything it wants in advance.
She also said: "You talked about the question of EU funds and EU funds that are currently intended to continue beyond the date at which we would be leaving the European Union.
"The Chancellor of the Exchequer set out very clearly some weeks ago what the position on this was - those funds will continue to be met provided they give value for money and meet the UK Government's objectives."
Mrs May said the Brexit process can take up to two years once triggered, with progress of the negotiations affecting the time needed.
She defended the UK's economic record, telling MPs it has the "fastest-growing" economy this year in the G7 before listing companies which have announced investment since June's referendum - including Nissan.
Mrs May added to Mr Corbyn: "Then you talk about confusion on the frontbench.
"Well, you've obviously been looking at your own frontbench when you consider this matter.
"Let's just take one very simple issue of immigration. The shadow home secretary (Diane Abbott) suggests freedom of movement should be maintained. The shadow chancellor (John McDonnell) said we should have a fair deal on freedom of movement. The shadow Brexit secretary (Sir Keir Starmer) said we should have immigration controls.
"They can't even agree on one aspect of the United Kingdom leaving the European Union.
"What I know is with your negotiation techniques if you were in office we'd sure as goodness be getting the worst possible deal that we could get for the United Kingdom."
Liberal Democrat leader Tim Farron accused the Prime Minister of pursuing a hard Brexit, which he dubbed "ludicrous" and an "extreme rewriting of the referendum result".
Mr Farron said: "Following the European Council, it does appear that the Prime Minister is leading our country not just out of the European Union, but also out of the single market and the customs union, neither of which were on the ballot paper last June.
"If instead, Remain had won by a whisker last June, would the Government have had a mandate, I wonder, for a 'hard Remain'?
"Would Mr Cameron now have been stood there, bouncing us into the euro and to Schengen, and will she agree that as ludicrous as this sounds, it is no more ludicrous than the extreme rewriting of the referendum result that she now seeks to impose on the British people?"
In response, Mrs May said : "The majority vote at the referendum was for the United Kingdom to leave the European Union. That is what we will be delivering.
"Once again, he raises questions about means rather than ends. What we want is the best possible outcome in terms of the trading relationship with the European Union, for the UK with the European Union, and for operating within the European Union.
"That is where our focus should be, not on particular processes to get there."
The Prime Minister also indicated she was in favour of Britain remaining part of Europol and the European Arrest Warrant, adding that this would be decided during Brexit negotiations.
But she again refused to say exactly when the plan for Brexit would be published, after questioning from Labour MP Angela Eagle (Wallasey).
Ms Eagle said: "Perhaps the Prime Minister, then, could tell us with some certainty when her plan for exiting the European Union, which she has agreed to present to this House, is actually going to be ready.
"Presumably it will be some time before she triggers Article 50?"
In reply, the Prime Minister said: "Yes."