The UK Labour party has called on the British Government to come clean with its plans for immigration after Brexit, as it urged ministers to put the economy at the heart of negotiations.
The Opposition is seeking to amend proposals allowing Theresa May to start formal Brexit talks by placing five key objectives at the heart of the Government's strategy.
These include maintaining a strong and stable economy, as well as continuing tariff-free trading arrangements with the European Union.
Labour's amendment, new clause two, also calls for a specific focus on cooperation in science and research, workers rights and maintaining peace in the North during the divorce deal.
Shadow Brexit minister Paul Blomfield said: "Our approach is to put the economy and jobs of the British people first and to get the right trading relationship with the EU."
Turning to immigration, he added: "The only real way of substantially reducing numbers is...to crash the economy, and it may be that will be the effect of the Government's negotiations.
"But assuming that is not their plan, they now need to come clean with the British people...on this red line - what is their plan?
"If taking control of immigration is what is defining this Government's approach to Brexit, the minister, in his closing remarks, needs to make clear, what are the Government's intentions?"
Mr Blomfield said his party backed the reasonable management of migration through the application of fair rules.
He added that concerns on immigration had been "relentlessly" talked up during the EU referendum campaign.
However, immigration from outside the EU had shown little change since the Conservatives came to power, despite the Government having the power to control it, he said.
"The Government needs to do all that it can to secure the jobs that depend on trading with our biggest and our closest partner, the European Union."
A second Labour amendment to the European Union (Notification of Withdrawal) Bill, new clause seven, calls on the Government to remain committed to cracking down on tax evasion and avoidance.
Labour has repeatedly raised concern about Britain becoming a tax haven after Brexit.
Mr Blomfield said the Government should not be forced into "a race to the bottom" on corporation tax.
Mr Blomfield said ministers need to explain their intentions on Euratom, the European nuclear research agency.
He said: "The people in this country deserve to know on Euratom.
"People voting in Copeland in a couple of weeks' time will want to know - their jobs are on the line."
Conservative former minister John Redwood said he agreed with Labour's amendment outlining priorities for the Government as it "makes perfectly sensible" statements about the UK's negotiating aims.
But he said: "Having excited them with my agreement, I will not actually be voting for this new clause."
Mr Redwood said he was happy with assurances from ministers, adding: "I think, although the words do not explicitly say 'This is what has to be delivered', if it's embedded in legislation the implication is that all these things have to be delivered - and some are not in the gift of this Government or this Parliament.
"I return to this point that the Opposition never seems grasp - we are all united in the aims of our trade being tariff-free but it will be decided by the other 27, not by this Parliament or by ministers."
The SNP has called for Gibraltar to consent to the Brexit process before triggering Article 50, as the British territory voted overwhelmingly to remain in the European Union during the referendum.
Joanna Cherry, who sits on the Brexit Committee, said it was vital for Gibraltar to play a role in the process and questioned why it was not mentioned in the draft legislation.
Ms Cherry said Scotland and Gibraltar had both voted in favour of remaining in the EU and both should be taken into consideration.
The Edinburgh South West MP said: "Scotland shares with Gibraltar a desire to be mentioned in the Article 50 letter and the big priority for Scotland is that the British Government take into account the Scottish Government's request for a differentiated deal for Scotland."
She went on: "Within the wider UK and wider dependencies, there are in fact some differentiated agreements, to go back to the case of Gibraltar. Gibraltar is in the European Union but not in the customs union."
Ms Cherry called for Scotland to remain in the single market after the rest of the UK leaves, saying there could be a compromise even if Scotland did not have a veto on the Brexit process.
Intervening, former shadow foreign secretary Hilary Benn said there was "no evidence" that the other 27 EU leaders would allow Scotland permission to remain in the single market after the rest of the UK leaves.
Responding, Ms Cherry said: "The other 27 member states are waiting for the United Kingdom to put its money where its mouth is and to come to the table and negotiate. They need us to put our own house in order before we do that."
The SNP amendment, new Clause 54, calls for the Chief Minister of Gibraltar to consent on the Brexit process before Article 50 is triggered.
Ms Cherry warned that the Government could face "a slew of legal claims" if they did not address the rights of EU nationals living in the UK before starting the Brexit process.
The SNP justice spokeswoman said: "I know that many honourable members opposite don't hold any great affection for the European Convention on Human Rights, but for the time being, even when we exit the European Union, we are still going to be signatories to it, and the British courts will still be bound by it.
"I am really just offering a helpful word of warning to the Government if they want to save some taxpayers' money that they might want to think very carefully about addressing this issue before they are met with a slew of legal claims."