The United Kingdom Supreme Court ruled Wednesday that diplomats who force staff to work in conditions of modern slavery cannot invoke diplomatic immunity to fend off compensatory claims.

The suit was brought by Josephine Wong, a Philippines national, against Saudi diplomat Khalid Basfar for forcing her to work for him and his family in abusive conditions. Wong alleged that she was confined to the house at all times, except for when she had to take out rubbish, and was made to work from 7 am to 11.30 pm every day, with no days off or rest periods. Wong further claimed that she wasn’t paid for seven months after her arrival in the UK. She was later paid a small fraction of her contractual entitlement in July 2017, but Basfar never paid her thereafter.

Wong brought a suit against Basfar in an employment tribunal for unpaid wages and violations of employment rights. Basfar opposed her claim by invoking his diplomatic immunity, a provision under Article 31 of the Vienna Convention on Diplomatic Relations which shields diplomats from criminal charges and many civil claims. However, “any professional or commercial activity exercised by the diplomatic agent in the receiving State outside [their] official functions” may be subject to civil lawsuits.

The employment tribunal ruled in Wong’s favor, but after Basfar successfully appealed the case before the Employment Appeals Tribunal, Wong was allowed to file an appeal with the Supreme Court.

In a majority of three to two, the Supreme Court held that the exploitation of a domestic worker for profit by a diplomat falls outside the scope of ordinary employment relationships and that Basfar is not immune from Wong’s suit.

In a summary of its judgment, the Supreme Court held “The extent of control over Ms Wong’s person and dominion over her labour exercised by Mr Basfar on the assumed facts of this case was so extensive and despotic as to place her in a position of domestic servitude.”

The court further noted:

On the assumed facts Mr Basfar gained a substantial financial benefit by deliberately and systematically exploiting Ms Wong’s labour for almost two years, initially for a fraction of her contractual entitlement to wages and latterly for no pay at all. This conduct is accurately described as a commercial activity practised for personal profit.

The court held that if the facts alleged by Wong are proved, Basfar will not be able to prevent compensatory claims by exercising his diplomatic immunity. The ruling is being touted as a major victory for campaigners and activists against modern slavery.