CIVIL rights group Liberty has lost an eleventh-hour court bid to hold Boris Johnson to Brexit law.

The organisation, formerly led by Labour peer Shami Chakrabarti, asked the Court of Appeal in London to allow an urgent hearing of its case to compel Boris Johnson to “act within the law” before it is “far too late”.

It sought to act before today’s crunch parliamentary vote on Johnson’s latest Brexit deal when MPs will sit in for specially convened day of business.

The charity announced plans to bring the case in September, saying it was “gravely concerned” by media reports which suggested Johnson intended to flout Brexit legislation.

Liberty aimed to ensure the Prime Minister complies with the Benn Act, which requires him to ask for an extension to the current October 31 Brexit deadline if Parliament does not approve his deal. But senior judges have refused to fast-track the case.

In a statement, the charity tweeted: “Today we asked Court of Appeal judges to ensure the PM obeys the law. They won’t hear our case now – but the fight continues.

“We’ll be watching what happens this weekend. The law is still the law and our case is standing by to hold the Gov to account.”

The case is separate to that taken to Scotland’s Court of Session by anti-Brexit campaigner Jo Maugham QC.

READ MORE: Scottish bid to halt the Johnson's Brexit deal debate in Parliament is lost

Government lawyers said Liberty’s case does not need to proceed urgently, as there is “ample time” for it to be heard before the UK’s planned exit from the EU on October 31.

Sir James Eadie QC, for the Prime Minister, said Johnson is “well aware of his duty to obey the law” and “is and will continue to be advised in the usual way on any issues as to the lawfulness of his proposed actions”.

No date has been set for the hearing of Liberty’s court challenge, but it could be as early as Monday.