A British mother of two is fighting deportation from Dubai where she has been jailed for adultery and stripped of custody of her sons.

Marnie Pearce, 40, began a three-month jail sentence in late February in the Muslim Gulf emirate, after being convicted of cheating on her husband.

Ms Pearce, who is originally from Bracknell, Berkshire, has denied committing adultery while married to her Egyptian ex-husband.

She told the British media she had thrown her husband out after discovering he was having an affair and claimed he had framed her to win custody of the children.

But in March 2008, her husband stormed the villa along with a police patrol while she was there with her alleged British lover. She insisted they were only having a cup of tea and that they never had sex.

Dubai is home to a large community of non-Muslim expatriates, but despite its reputation for extravagance and relative tolerance still adheres to certain Islamic traditions through tough rulings.

In October 2008 a British couple received three month jail sentences for having sex on a beach in Dubai. They were found guilty of having sexual intercourse outside marriage and offending public decency. They were also fined £200 for drunkenness and ordered to be deported from Dubai on their release.

A petition demanding the immediate release of Ms Pearce and the lifting of the deportation order has been signed so far by 4,700 people. It will be handed to the United Arab Emirates embassy in London on Thursday.

The petition was launched online on March 25, a week after Dubai's highest court upheld her jail sentence and subsequent deportation.

The same day, a Dubai family court, which applies Islamic Sharia law, ordered the couple’s divorce and stripped Ms Pearce of all custody rights over her sons Laith, seven, and Ziad, four.

Under Islamic law, a Muslim mother may be given custody of daughters under the age of nine and sons under seven, after which custody goes to the father.

But mothers can lose such rights if they are deemed incompetent to raise children, according to a legal website offering advice on international custody rights.

Amnesty International said that even if Ms Pearce was involved in a sexual relationship out of wedlock, she should not face criminal punishment.

"The legal provisions that provide for imprisonment over sexual activities are in our view flawed... and create a prisoner of conscience," Amnesty International researcher Drewery Dyke said.

"In many jurisdictions, this is not criminalised and dealt with in civil courts," he said. "It is becoming increasingly incompatible (with human rights standards) to have laws that criminalise consensual sex."

Mr Dyke said priority should be given to serving the interests of the children, according to an international convention on child rights, which the UAE became party to in 1997 with some reservations.

The British Foreign Office said Ms Pearce may appeal the custody judgement.

"We've been working hard in Marnie's case, both through repeated representation to the UAE authorities and consular assistance to Marnie and with her family," it said.

The British embassy has sent a letter to the Dubai attorney general asking for the deportation ruling to be lifted, according to Ms Pearce’s friend.

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