Of 11 justices, eight ruled in favour of consulting parliament and three against.
The British government has lost its legal battle to start the Brexit process without going through parliament.
Media outlets have reported that several versions of a bill have been drafted to put to lawmakers.
The Guardian newspaper has claimed ministers had privately conceded they were very likely to lose the case at the Supreme Court and had drawn up at least two versions of a bill to be presented to parliament after the ruling.
A “short bill”?
During the Supreme Court appeal hearing in December, government lawyer James Eadie said a “one-line” bill would be a solution if judges ruled parliament had to give its assent to the triggering of Article 50.
Ministers are reportedly hoping the ruling will allow Prime Minister Theresa May to put forward a short bill or motion, narrowly focused on Article 50.
They say this would make it difficult for lawmakers to amend, making its passage through the House smoother and swifter.
However, government lawyers are reported to have advised the prime minister that a short, or single-clause, bill could store up future problems.
A “soft Brexit”?
Those in favour of a clean break with the EU are concerned that parliament could use the Supreme Court ruling to water down the government’s plan, in favour of a so-called “soft Brexit”, with more lenient terms negotiated.
The majority of lawmakers were in favour of remaining in the EU.
Why was the UK Supreme Court involved?
Because of a legal argument.
Those against the result of last June’s referendum argued that triggering Article 50 – the official process by which a member state can leave the EU – would nullify the 1972 act of parliament that began the procedure for the UK to join.
They said this can only be done by parliament and not by a popular referendum.
In the UK, only parliament has the power to “make and unmake laws” – in other words, to give its permission for its act to be undone.
London’s High Court backed that argument.
This prompted the government to appeal to the Supreme Court, Britain’s highest judicial body, in December. (Euronews)