The use of Sharia, or Islamic religious law, is growing in Britain, with thousands of Muslims using it to settle disputes each year, but women's groups and some others are objecting.
''You must speak the truth, sister. Because Allah is listening to your every word, you can lie to us but not to Him.''
The bearded sheikh is instructing his first client of the day to explain why she is unhappy in her marriage.
Sitting behind a small desk in the back room of a converted terrace house, Sheikh Haitham al-Haddad is a representative of the Islamic Sharia Council, the largest Sharia body in the UK, based in Leyton, east London.
The woman has come to the council for an Islamic divorce because her husband refuses to grant her one.
''I'm not happy. He's never at home and I've seen messages from other women on his phone. He doesn't even give money to help support the kids,'' the woman tells the sheikh.
It is easier for a Muslim man to end a marriage in Islam, but a wife must persuade the judges to grant her a dissolution if her husband is opposed to divorce.
The case is typical of those case dealt with by Sharia councils, as thousands of Muslims are turning to them to help resolve family, financial and commercial problems in accordance with Sharia principles.
An estimated 85 Sharia councils could be operating in Britain, according to a 2009 report by the think tank Civitas.
Several bodies like the Islamic Sharia Council have seen a large increase in their cases in the past five years.
''Our cases have easily more than tripled over the past three to five years," says Sheikh al-Haddad.
''On average, every month we can deal with anything from 200 to 300 cases. A few years ago it was just a small fraction of that.
''Muslims are becoming more aligned with their faith and more aware of what we are offering them,'' he explained.
The principles of Sharia govern all aspects of a Muslim's life. It is derived from a combination of sources including the Koran, the Hadith, which is based on the example of the prophet Muhammad, and fatwas, which are rulings of Islamic scholars.
Sharia has been operating in the UK, managed by locally-appointed councils, in parallel to the British legal system since 1982.
But the informal councils have no legal powers and they cannot impose any penalties.
They deal with civil cases alone, but many Muslims are choosing to voluntarily accept rulings made by the scholars.
Omar Hannan, 28, from Solihull, turned to Sharia instead of the British courts after an ownership dispute broke out between the British Muslim partners at his industrial cleaning company.
''It fulfilled my Islamic spiritual principles which was the main reason I went to a Muslim tribunal.
''But it was also very quick. We resolved it in three to four months,'' he said.
''It only cost a couple of hundred pounds, and you can imagine how much it would have cost through the English legal system,'' he added.
As a demand for Sharia thrives, a number of British law firms are starting to tap into the booming market.
Muslim Lawyer Aina Khan has launched one of the first Sharia departments at her London-based law firm.
She offers clients advice that is in keeping with both English and Islamic law.
''I am surprised that the majority of people that I am dealing with are under the age of 50. They are British Muslims who want to satisfy their British identity as well as their Muslim one.
''So I give them solutions to their problems that satisfy both legal systems all under one place.''
Despite the growing demand for Sharia law in Britain, there is also increasing opposition by some groups who argue that the practice discriminates against women.
The Iranian and Kurdish Women's Rights Organisation (IKWRO) is campaigning to bring an end to the practice.
''We have spoken to many women and all of them tell us the same story; Sharia law is not providing them with the justice they seek. The councils are dominated by men, who are making judgements in favour of men,'' said Diana Nammi.
Concerns such as these have led crossbench peer Baroness Cox to introduce a bill before the House of Lords, aimed at introducing regulation of Sharia organisations in the UK.
The bill has received its first reading and is expected to get a second reading later this year.
But for groups like IKWRO the bill does not go far enough.
''We think there shouldn't be any religious law practising in Britain - all Sharia bodies should be banned. That is the only way we can ensure equality of justice for all women," argues Diana Nammi.
But while a demand for Sharia continues in Britain, Sheikh Haitham al-Haddad says the practice cannot be banned.
''We are not forcing people to walk through our doors. They are voluntarily coming to us,'' he said.
''If you ban us, then British Muslims will find somewhere else to go.
''Many will go to Muslim countries abroad, where there will be no way to protect them.''