The UK’s most senior judge has condemned law firms that demand female lawyers wear high heels, as she lamented the lack of “progress” on sex discrimination in the legal profession.

Baroness Hale, who is about to retire as president of the Supreme Court, said in an interview said she was also “shocked” some women barristers were paid less money than their male counterparts for similar work.

“I’ve heard some shocking stories about women barristers being charged out at lower rates for the equivalent work and they’re not realising because they don’t know what their clerks are asking for their male counterparts,” she told the Evening Standard.

Women advocates were also not being given the opportunity to tackle the biggest and most significant cases, including those argued before the Supreme Court, Lady Hale said.

This could not be put down a lack of capable barristers because some firms have consciously tried to instruct equal numbers of men and women “and it works perfectly well”, she added.

Supreme Court verdict: Boris Johnson prorogation unlawful Show all 16 1 /16 Supreme Court verdict: Boris Johnson prorogation unlawful Supreme Court verdict: Boris Johnson prorogation unlawful The Supreme Court has ruled against Boris Johnson by declaring his government unlawfully shut down parliament for five weeks EPA Supreme Court verdict: Boris Johnson prorogation unlawful Lady Hale handed down the historic verdict, hailed by opposition MPs and anti-Brexit campaigners. She said all 11 judges were unanimous in deciding that the case is “justiciable”, so the government loses that part of the argument. “The court is bound to conclude therefore that the decision to advise Her Majesty to prorogue was unlawful because it had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions.” EPA/Supreme Court Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller and her team react outside the Supreme Court are the verdict. She said: “Today is not a win for any individual or cause. It is a win for Parliamentary sovereignty, the separation of powers and independence of our British courts. Crucially, today’s ruling confirms that we are a nation governed by the rule of law, laws that everyone, even the Prime Minister, are subject to." PA Supreme Court verdict: Boris Johnson prorogation unlawful A person dressed as a caricature of British Prime Minister Boris Johnson in a prison uniform stands outside the Supreme Court AP Supreme Court verdict: Boris Johnson prorogation unlawful Labour leader Jeremy Corbyn called for Mr Johnson to “consider his position” following the landmark decision, while Lib Dem leader Jo Swinson said he was “not fit to be prime minister” Getty Supreme Court verdict: Boris Johnson prorogation unlawful Scottish National Party (SNP) Westminster leader Ian Blackford raises his arms as he comes outside. He said: "This is an absolutely stunning judgement by the Supreme Court today." He went on to say, "we all want to get back to work, and quite frankly, on the back of this, Boris Johnson must resign immediately." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Crowds outside celebrated the verdict AP Supreme Court verdict: Boris Johnson prorogation unlawful Delegates at the Labour party conference applaud after hearing the news AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Speaker John Bercow said MPs must now “convene without delay” and confirmed the Commons would return at 11.30am on Wednesday AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller said: "“As a result of this judgment, Parliament is open, it was never prorogued. I urge MPs to get back to work immediately.” AP Supreme Court verdict: Boris Johnson prorogation unlawful MPs Anna Soubry, Liz Saville Roberts and Caroline Lucas, together with SNP leader Ian Blackford, react. Green MP Caroline Lucas has said the Supreme Court’s decision is “just the start” Reuters Supreme Court verdict: Boris Johnson prorogation unlawful “The UK deserves a Prime Minister and a Government who act with honesty, integrity and in a manner consistent with our constitution, at all times." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Anti-Brexit supporters react as they gather outside the Supreme Court in London, Tuesday, Sept. 24, 2019 as it makes it's decision on the legality of Prime Minister Boris Johnson's five-week suspension of Parliament. (AP Photo/Frank Augstein) Frank Augstein AP Supreme Court verdict: Boris Johnson prorogation unlawful The SNP’s Joanna Cherry QC says: “Boris Johnson’s position is untenable and he should have the guts to resign.” PA Supreme Court verdict: Boris Johnson prorogation unlawful epa07865617 Protesters react outside the Supreme Court after the result of a hearing on the prorogation of parliament, in London, Britain, 19 September 2019. The Supreme Court ruled that the suspension of parliament by British Prime Minister Boris Johnson was not lawful. EPA/NEIL HALL NEIL HALL EPA Supreme Court verdict: Boris Johnson prorogation unlawful Tom Tugendhat MP returned to the chamber in the House of Commons within minutes of the Supreme Court ruling PA

The judge warned that women in law were still being held back by antiquated notions of smart dress.

“Yet one does again hear stories of women being required to wear high heels by employers," she added.

“Requiring neatness, tidiness, cleanliness is one thing, requiring a particular image is another.”

Baroness Hale has been a member of the Supreme Court since its inception in 2009 and its president since 2017.

During that time she has presided over a string of politically weighty cases, including the Miller judgments over whether the government could trigger Article 50 and kickstart the Brexit process, and more recently the case which saw Boris Johnson’s effort to prorogue parliament deemed unlawful.

When asked what her proudest achievements on the UK’s highest court she cited both those cases.

She also revealed she hopes to use her retirement from the Supreme Court to write a memoir. Baroness Hale will also take up an honorary position as a professor of law at University College London.

Beyond the legal profession, the 74-year-old said she expected the courts would push ahead on entrenching greater equality in the law.

Lady Hale at her own valedictory ceremony in the Supreme Court (PA)

Many issues such as non-discrimination, workplace harassment and equal pay have been on the statute book for a while but were yet to be put into practice, she suggested.