Young Iraqi girls are being sold for sex in temporary 'marriages' that can last as little as an hour, a BBC documentary has revealed.

Shia clerics were filmed offering 'pleasure marriages' in which men, usually banned from having sex outside marriage, can pay a dowry for an interim wife.

One cleric claimed it would be 'no problem at all' to marry girls as young as nine under Islamic law.

The practice is banned in Iraq but eight out of 10 Shia clerics who were approached were willing to carry it out - and one of them even offered to help procure young girls, the BBC News investigation found.

The religious rite dates back centuries, partly intended to allow men to have a legitimate relationship while away from their wives.

However, some Iraqi men and Shia clerics are now abusing it to give a veneer of legitimacy to child prostitution.

One cleric in Karbala, an important religious site in Iraq, told the undercover BBC journalist that girls as young as nine could be subject to the procedure.

'According to Sharia, there's no problem,' he said, when asked if it was acceptable to conduct a temporary marriage with a young girl.

When the reporter voiced concern that he was exploiting the girl, the cleric told him: 'No way'.

Another cleric, also filmed secretly, was asked if a temporary marriage with a 13-year-old virgin would be permissible under Islamic law.

'Just be careful she doesn't lose her virginity,' the cleric replied, suggesting other forms of sexual interaction instead.

Asked about 'marrying' a young girl, one cleric told an undercover reporter that 'nine years plus, there's no problem at all' under Islamic law

Asked what happens if the girl gets hurt, the cleric said: 'That's between you and her.'

Later in the documentary, that second cleric went even further and offered to help procure the girls as well as conducting the marriages.

Offering to take a photo of a girl and send it to the undercover client, he added: 'Then when you come back, she's yours.'

That cleric also reassured the reporter that there was no child exploitation taking place.

'She was willing and you paid her,' he said.

The length of the marriage must be specified in advance, and can be fixed at anything from one hour to 99 years.

Some girls said that clerics had provided them with contraceptive injections to ensure they did not become pregnant.

One cleric went even further and offered to help procure the girls as well as conducting the temporary marriage

The practice is not permitted under Sunni Islam and was banned under Saddam Hussein's Sunni-led government.

However, the practice flourished in the wake of the 2003 invasion as Iraq's new government struggled to impose its authority on the country and Shia clerics grew in influence.

One girl said she could not even remember how many times she had been 'married' and said she relied on the dowries for her income.

Young women also fear that losing their virginity in a temporary marriage will leave them unable to find a permanent husband in future.

One 14-year-old said she feared the consequences if a future husband found out that she was not a virgin.

However, an Iraqi government spokesman said there was little that authorities could do if girls did not complain to the police.

'If women don't go to the police with their complaints against clerics, it's difficult for the authorities to act,' they told the BBC.

Undercover With The Clerics - Iraq’s Secret Sex Trade is on BBC iPlayer