The Brexit Secretary has warned members of Parliament to leave the bill for exiting the European Union unchanged when it is debated again in the House of Commons on Monday.
David Davis issued a last-minute warning to Tory rebels not to sabotage the Article 50 Bill amid fears that any change could see Brexit end up in the courts, reported The Telegraph on Sunday.
Davis said that putting promises over leaving the EU into law creates a "greater risk of legal action".
Davis warned that Prime Minister Theresa May would be negotiating with "one hand tied behind her back" if MPs approve two changes to the law proposed by Lords.
He also said that protecting the rights of EU citizens in Britain without reciprocal promises would plunge more than a million Britons abroad into "uncertainty".
"There will be many opportunities for Parliament to debate the ins and outs of our negotiation of a new partnership with the EU, and influence the outcome," Davis said.
"But attaching conditions to a bill that simply allows the Prime Minister to start the process of implementing the referendum result is emphatically not the way to do it."
The shot across the bows comes ahead of a historic week in the Parliament that is expected to see Britain's withdrawal from the EU approved by MPs and peers, reported the newspaper.
May is preparing to formally start negotiations as early as Tuesday in a landmark moment in Britain's modern history, dubbed "independence day" by supporters.
However, before that can begin, MPs must vote on Monday on whether to make two amendments to the legislation giving the Prime Minister the power to start Brexit.
The first would demand proposals are published within three months to protect the rights of all EU citizens currently in Britain.
The second would give MPs and peers a "meaningful vote" on the final Brexit deal — effectively a veto, as Britain's departure could not happen without a parliamentary vote.
Both are being opposed by the government, but pro-EU Tories are rallying support privately behind both changes. Only about 30 Tory MPs are needed to back the changes for them to pass, given opposition parties support them and the Conservatives have such a slim majority, said the report.
May has indicated the Parliament will get a say, but has said she would rather "walk away" from the EU than accept a "bad deal", and would not return to negotiations if MPs and peers reject the Brexit package.
The bill could complete its final stages on Monday if the Lords accepts the decisions made by MPs.