MPs may need to draw up further legislation to prevent Boris Johnson from forcing through a no-deal Brexit, Sir Ed Davey has said.
The Liberal Democrat deputy leader said there were some concerns the backbench bill to prevent a disorderly Brexit next month was "not watertight".
Rebel MPs derailed the prime minister's Brexit plans by passing the act, tabled by Labour's Hilary Benn, which compels him to seek a three-month extension if he cannot secure a deal by 19 October.
The move came ahead of Mr Johnson decision to prorogue parliament, which was sensationally overturned by the Supreme Court in a historic ruling.
Opposition MPs are withholding consent for an early election until Mr Johnson has sought an extension from Brussels as distrust between parliamentarians and No 10 hit new lows.
Sir Ed told the Today programme: "The key thing of course is implementing the extension of article 50 so that we can get no-deal totally off the table.
“It might need an extra law, who knows? The key thing is the implementation of the extension of article 50.”
Asked if the bill was watertight, Sir Ed said: “I’ve certainly seen the opinion of a number of very notable lawyers, that it’s not watertight – and if that’s the case we may need another bill to ensure that no-deal Brexit is completely taken off the table.
"But even with another bill, we have to force the prime minister to extend article 50 to get to this implementation, as well as the law."
Despite calls for Mr Johnson to quit, opposition leaders are reluctant to table a motion of no confidence to oust him in case he refuses to comply with the provisions set out in the Benn act.
MPs are also split over who could lead a temporary government if Mr Johnson was deposed, as the Lib Dems have refused to put Jeremy Corbyn in No 10.
Mr Corbyn said: "Until it is very clear that the application will be made, per the legislation, to the EU to extend our membership to at least January, then we will continue pushing for that and that is our priority.
"When that has been achieved we will then be ready with a motion of no confidence."
