A Bradford solicitor spoke of her “extreme concern” after an imam in Heckmondwike was apparently recorded agreeing to conduct a marriage ceremony involving a 14-year-old girl.

Shams-Ul-Huda Khan Mishabi, who preaches at the Jamia Masjid Kanzul Iman Mosque, is one of a number of Muslim clerics filmed by undercover reporters seemingly agreeing to perform an Islamic marriage, or Nikkah, between a girl of 14 and an older man.

Footage appears to show him telling reporters that under Sharia law, the girl can go ahead with the ceremony to a 20-year-old man from London, who he is told she has only met once.

The reporters were from the ITV programme Exposure and the show will be broadcast tomorrow. The mosque said it has launched a “thorough investigation” and does not endorse forced or underage marriage.

However, reporters for the programme, who posed as the mother and brother of the teenager, claim 18 of 56 mosques they approached agreed to conduct ceremonies.

Nazia Shaukat, a family law specialist at Petherbridge Bassra solicitors in Bradford, said she was aware of cases of forced and under-age marriages involving girls aged 16 and under in Bradford and the surrounding area.

On the claims, she said: “Marriage involving people under the age of 16 is illegal, a 14-year-old is still a child. I haven’t seen the documentary, but it’s extremely concerning.”

Last month, Petherbridge Bassra held a seminar on forced marriage and honour-based violence and Ms Shaukat said it had seen an increase in requests for help to prevent forced marriages.

Forced marriage is not a crime, but civil courts can issue a Forced Marriage Protection Order to protect anyone at risk of being coerced into a marriage or who has been involved in a forced marriage. Anyone who breaches an order can be arrested.

“We see girls under the age of 16 and girls that have just turned 16,” she said. “It’s an age when they are just leaving school and they can go off the radar because no one will notice.”

Mohammed Rafiq Sehgal, of Bradford’s Council for Mosques, said British Muslims should respect the country’s legal age for marriage, which is 16.

He said Nikkah is an act by consent of both parties, so any element of force or coercion would make the union void.

“In all matters, the law of the land must take precedence,” he said.

A West Yorkshire Police spokesman said officers supported people through 129 incidents of forced marriage and honour-based violence in the first six months of this year. On the issue of forced marriage, he added: “It is a form of domestic violence and sometimes also of child sexual exploitation. West Yorkshire Police stand together alongside partners in the condemnation of forced marriage and are united in doing everything possible to protect people involved in forced marriage.”