Outpouring of emotionspublished at 10:23 British Summer Time 16 April

10:23 BST 16 April

Philip Sim
BBC Scotland political correspondent, at the Supreme Court

Image source, PA Media

The campaigners broke into applause as the judges left the courtroom.

All had been warned not to disrupt proceedings while the court was in session, but there was an immediate outpouring of emotion afterwards.

The For Women Scotland team were in tears, quickly enveloped in a group hug.

Lord Hodge said the ruling should not be seen as a triumph for one group over another, but the cheering and singing has spilled out onto the street outside the court - this is clearly being celebrated as a win by the group.

Remarkable scenes inside Supreme Courtpublished at 10:21 British Summer Time 16 April

10:21 BST 16 April

James Cook
Scotland editor

There were remarkable scenes inside the Supreme Court after the judges left the bench. Campaigners who had brought this case hugged each other and punched the air. Several of them were in tears.

Susan Smith of For Women Scotland told me: “It’s almost unbelievable after so many years to finally have got a ruling which reflects everything we’ve always said.”

Lord Hodge has now concluded the judgement by saying that they have allowed the appeal by For Women Scotland, having outlined a number of reasons why.

The court then adjourns.

For Women Scotland have won the case against the Scottish governmentpublished at 10:20 British Summer Time 16 April

10:20 BST 16 April

Philip Sim
BBC Scotland political correspondent, at the Supreme Court

There was an audible intake of breath in the courtroom as Lord Hodge announced that the Equality Act’s definition of a woman is based on biological sex.

There were pats on the back from fellow campaigners for the representatives of For Women Scotland, and the group's director, Marion Calder, wiped away a tear.

The group’s appeal to the highest court in the land has been successful - they have won the case against the Scottish government.

Lord Hodge says the predecessors to the Equality Act used definitions of biological sex, and gender reassignment was added as a separate protected characteristic.

He tells the court that, after “painstaking analysis”, including people with a Gender Recognition Certificate in the sex group would make the Equality Act read in an “incoherent way”.

He says that issues relating to pregnancy and maternity can only be interpreted as referring to biological sex, while other parts of the Equality Act refers to "certificated sex" as well.

"As I shall explain later in this hand down speech, the Equality Act 2010 gives transgender people protection, not only against discrimination through the protected characteristic of gender reassignment, but also against direct discrimination, indirect discrimination and harassment in substance in their acquired gender," Lord Hodge says.

"But we counsel against reading this judgement as a triumph of one or more groups in our society at the expense of another, it is not."

UK Supreme Court judge Lord Hodge announces that the Equality Act’s definition of a woman is based on biological sex.

He counsels not to see this as a triumph for one side over another and stresses the law still gives trans people protection against discrimination.

Judges at the UK Supreme Court have begun delivering a landmark ruling on the legal definition of a woman after a challenge brought against the Scottish government.

The appeal at the Supreme Court before Lord Reed, Lord Hodge, Lord Lloyd-Jones, Lady Rose and Lady Simler was heard last November and, after the two-day hearing, the judges said they would "take time to consider very carefully" before issuing their judgement on 16 April.

The UK Supreme Court is about to deliver its landmark verdict on how a woman should be defined in law.

The ruling, which comes after a long-running legal battle between the Scottish government and a women's group, could have far-reaching implications on how sex-based rights apply across Scotland, England and Wales.

Our reporters in court and correspondents will be on hand to explain what's in the judgement and its implications.

You'll also be able to follow the ruling right here, just click watch live at the top of the page.

Legal teams are gathered in courtpublished at 09:43 British Summer Time 16 April

09:43 BST 16 April

Philip Sim
BBC Scotland political correspondent, at the Supreme Court

The legal teams have gathered in court one, under stained glass windows, carvings of angels and an imposing portrait of a Duke of Wellington (the son of the famous one).

Both sides say they are in the dark about the outcome; there has been no sneak peek under embargo even for the groups who brought the case.

The room is packed as we wait for the judges - but the For Women Scotland case will be the second judgement handed down, probably closer to 10am.

Image source, PA Media

Gender reform has become a political battleground in recent years, particularly in Scotland.

The Scottish Parliament passed the Gender Recognition Bill by 86 votes to 39 in December 2022 in an attempt to streamline the process for changing legal gender in Scotland.

However the UK government then blocked the bill, saying it would impact equality laws across Great Britain.

That sparked a legal fight that went to the Court of Session in Edinburgh, where the Scottish government's challenge to the veto was rejected.

With an election at Holyrood looming next year, today's verdict will likely provide a political talking point for parties ahead of going to the polls.

This morning's verdict will almost certainly have implications for political parties on a UK level too - UK ministers will be watching closely in terms of how it pitches future policies on gender reform.

Campaigners arrive to see rulingpublished at 09:19 British Summer Time 16 April

09:19 BST 16 April

Philip Sim
BBC Scotland political correspondent, at the Supreme Court

A large number of campaigners have arrived at the Supreme Court for the ruling.

As well as For Women Scotland, prominent gender-critical voices including Father Ted writer Graham Linehan and former SNP MP Joanna Cherry are queuing to get through the airport-style security.

There are serving politicians present too, with Tory MSP Pam Gosal in the queue.

A group of women with feminist flags and banners gathered to sing songs next to a statue of suffragette Millicent Fawcett in Parliament Square, right across the road from the court.

There will be real-world consequencespublished at 09:15 British Summer Time 16 April

09:15 BST 16 April

Philip Sim
BBC Scotland political correspondent, at the Supreme Court

Today’s ruling concerns what a woman is in the Equality Act but it’s also worth considering what the law is.

There’s the letter of the law, as drafted and agreed by parliament.

There’s the proper interpretation of that law, as adjudicated by the courts.

Then there’s the application of the law in “real life”, on the ground.

The latter is really the important thing, and the judges will be all too aware that their words will be closely scrutinised for their real-world consequences.

But it’s also worth remembering that the chain begins in parliament - if politicians don’t like the law, they can change it.

And regardless of how the ruling goes this morning, the debate is likely to move back into the political arena.

Image source, Getty Images

For Women Scotland formed in 2018 as a response to the gender recognition act proposals, and began holding public meetings the following year.

Since forming the group have consistently argued for women’s only spaces and that giving transgender people further rights will “erode” women’s rights in the process.

Among their actions are writing to Scottish councils to ask for single-sex toilets in schools and seeking to remove trans women from the definition of women in the Gender Representation on Public Boards (Scotland) Act 2018.

They have been backed by a number of famous campaigners, including Harry Potter author JK Rowling and Father Ted creator Graham Linehan.

Image source, Getty Images

The ruling, to be announced at about 09:45, is expected to set out how the law should treat transgender people.

The legal arguments have come at a time of heated debate on gender issues.

The Supreme Court is deciding on the proper interpretation of the 2010 Equality Act, which applies across Britain.

The law provides protection against discrimination on the basis of various characteristics, including "sex" and "gender reassignment".

The Scottish government argues transgender people with a gender recognition certificate (GRC) are entitled to sex-based protections, while For Women Scotland argues they only apply to people that are born female.

Image source, PA Media

The legal dispute began in 2018, when the Scottish Parliament passed a bill designed to ensure gender balance on public sector boards.

For Women Scotland complained that ministers had included transgender people as part of the quotas in that law.

After several cases in the Scottish courts, the issue has been sent to the Supreme Court in London for a final ruling.

For Women Scotland has warned that if the court sides with the government, it would have implications for the running of single-sex spaces and services, such as hospital wards, prisons, refuges and support groups.

Transgender people have warned the case could erode the protections they have against discrimination in their reassigned gender.

The UK Supreme Court is to deliver a verdict on how a woman should be defined in law at about 09:45 this morning.

It will mark the end of a long-running legal dispute between the Scottish government and a women's rights group which started with a relatively niche piece of legislation at the Scottish Parliament, but which could have considerable implications for the UK.

The decision will set out exactly how the law is meant to treat transgender people, and what it really means to go through the gender recognition process.

Further implications could include how it affects the running of single-sex spaces and services, and how measures aimed at tackling discrimination will operate in future.