Islamic faith marriages are not valid under English law, the court of appeal has ruled, in a blow to thousands of Muslim women who have no rights when it comes to divorce.

The judgment, delivered on Friday, overturned an earlier high court ruling that an Islamic marriage, known as a nikah, fell within the scope of English matrimonial law.

The appeal court has confirmed that nikah marriages are legally “non-marriages”, meaning spouses have no redress to the courts for a division of matrimonial assets such as the family home and spouse’s pension if a marriage breaks down.

Many couples who undergo nikah ceremonies believe they are lawfully married. But their marriages are only legal if they additionally go through a civil ceremony.

Responding to the appeal court judgment, Charles Hale QC, of the family law firm 4PB, said: “This means that many have absolutely no rights at the end of what they believe to be their ‘marriage’. No rights to assets in the husband’s sole name, and no rights to maintenance.”

The appeal court had “upheld the existing concepts of what constitutes a lawful marriage … The law in these cases is not keeping up with society. These vulnerable women need better protection than the law currently provides.”

The 2018 high court case concerned a couple, Nasreen Akhter and Mohammed Shabaz Khan, who had undergone a nikah marriage conducted by an imam in front of 150 guests at a restaurant in Southall, west London, in 1998.

The relationship had broken down, and Akhter petitioned for divorce. But Khan blocked the move, arguing the couple were not married under English law, only under sharia or Islamic law.

Akhter said she had seen Khan as her husband, and he had “always introduced me as his wife”.

The high court heard the couple had intended to follow their nikah ceremony with a civil ceremony, but that Khan refused to go through with a legal process despite frequent efforts by Akhter to persuade him.

Mr Justice Williams, who heard the case in the family division of the high court in London, concluded the marriage fell within the scope of the Matrimonial Causes Act 1973.

Under the law, there are three categories of marriage: valid, void and non-marriage. Valid marriages may be ended by a decree of divorce; void marriages may be ended by a decree of nullity; non-marriages cannot be legally ended because legally the marriage never existed.

The high court ruled the Akhter-Khan marriage had been “entered into in disregard of certain requirements as to the formation of marriage. It is therefore a void marriage and the wife is entitled to a decree of nullity”.

An appeal against the high court ruling was brought by the attorney general.

Three family judges sitting in the court of appeal concluded that to uphold the high court’s ruling “would gravely diminish the value of the system of registration of marriages upon which so much depends in a modern community”. It added: “It is not difficult for parties who want to be legally married to achieve that status.”

The state did not have a human rights obligation to recognise religious marriage, the judgment said.

Daniel Jones, of the law firm BLM, said the appeal court judgment was “a real blow for all concerned”.

He added: “The decision … will leave Muslim women in the UK in legal limbo, compelled to turn to sharia councils to pursue Islamic divorce. This often involves lengthy delays and does not afford women the same financial protections as would be granted if their ceremonies were recognised as a marriage under English law.

“This matter is of fundamental importance to Muslim women across the UK … leaving many women at great financial risk in unhappy relationships.”

Anna-Laura Lock, a senior associate at the law firm Winckworth Sherwood, said: “Given the current law on marriage leaves parties to a religious ceremony so exposed financially following relationship breakdown, this will not be the end of the road for this issue. A change in the law is long overdue and must surely be on the horizon.”

The law on marriage was “no longer fit for purpose in a modern, multicultural and less religious society”, she added.

Pragna Patel of Southall Black Sisters, an organisation that has campaigned on the issue of nikah marriages, said: “Today’s judgment will force Muslim and other women to turn to sharia ‘courts’, which already cause significant harm to women and children, for remedies because they are now locked out of the civil justice system.

“What we are seeing is the outsourcing of justice on family matters to unaccountable and fundamentalist-inspired community-based systems of religious arbitration. This is not about recognising religious marriages; it is about the state guaranteeing equality to all before the law.”

In 2018, an independent review of sharia councils recommended that Muslim couples should undergo a civil marriage as well as a religious ceremony to give women protection under the law.

The review, instigated by Theresa May in 2016 when she was home secretary, found that a significant number of Muslim couples did not register their marriages under civil law, and “some Muslim women have no option of obtaining a civil divorce”.

Raghad Altikriti, president of the Muslim Association of Britain, said many Islamic centres in the UK had made civil registration a condition of nikah marriage. The appeal court ruling provided an “opportunity to continue the discussion to ensure that everyone’s rights are protected by facilitating a comprehensive system that incorporates the needs of all”, she added.