Just over a year after Britons voted to leave the European Union, the United Kingdom government on Thursday unveiled the first piece of legislation to make it a reality - a 62-page bill that opposition politicians are already vowing to block.
Robert Bell, partner at global firm Bryan Cave, said the most controversial element of the bill would be those powers allowing ministers to fast track the implementation of certain European Union laws into domestic law through regulations without parliamentary debate, sometimes referred to as Henry VIII powers.
In a statement, Ms Longfield said: "The EU said they wanted to make residence rights of EU nationals the first thing to be agreed during the negotiations".
However, Mr Davis has previously stressed this is not the aim, saying: "To those who are trying to frighten British workers, saying, "When we leave, employment rights will be eroded", I say firmly and unequivocally, "no they won't'".
The first ministers and Labour leader Jeremy Corbyn were in Brussels Thursday for separate meetings with the EU's chief negotiator Michel Barnier, although he insisted he would only negotiate with May's government.
Ms Sturgeon and Mr Jones said they "agree we need a functioning set of laws across the United Kingdom after withdrawal from the EU" but said new devolved powers had to be agreed "through negotiation and agreement, not imposition".
Another key issue is that the bill does not include the EU Charter of Fundamental Rights.
Commenting the Bill, Caroline Lucas, the co-leader of the Green Party, has said that there is an "environment-shaped hole" in the proposals, and expressed concerns over the enforcement of environmental laws in future.
Her government said the bill is created to ensure that "as far as possible, the same rules and laws will apply on the day after exit as on the day before".
However, ministers will have their powers time-limited under a two-year "sunset clause" in the bill, and will only be able to make changes where technical problems arise because of the transfer of European Union regulations - not because they don't like them.
MINISTERS will grab sweeping "Henry VIII" powers to bypass MPs and make more than 1,000 changes to European Union legislation, under a historic Brexit law unveiled today.
"Nobody is seeking to frustrate the process; we are determined to ensure that the right approach is taken; and this is all about protecting the rights of citizens in Britain", Starmer told the Guardian.
There is now around 20,000 European Union legislative acts in force with around 5,000 applying in the UK. Labour has, so far, not indicated whether it will vote with the Government but has consistently said it will not attempt to frustrate the Brexit process.