An Indian nanny who claims she was treated as a slave by a high-profile civil servant in Britain has appealed against an employment tribunal hearing that threw out her original claim.

Shibani Rahulan, a senior legal adviser at the Department of Health, had been accused of treating Pratima Das as a slave.

Das, Rahulan's nanny and cleaner, claimed that her employer confiscated her passport and forced her to work for up to 15 hours a day. She was also subject to physical and verbal abuse by the lawyer and her partner, Rex Waldron, she said.

Das said that she escaped from her employer in 2008 following a heated argument that became violent. Legal battles, first to seek asylum in the UK - a claim that is still pending - and then bringing a case at an employment tribunal, have been going on ever since.

Das has applied to have her original employment claim re-heard, saying she was badly advised the first time. She lost that case in 2010 when the employment tribunal ruled that she had lied to the panel.

Waldron, a lawyer at the Department of Work and Pensions, said: "Pratima lived as a member of the family. We've got photographs of her at all of our parties and family gatherings - does she look like she's here under duress? As a slave? It's ridiculous.

"Her passport was kept with all of the family passports in the house. She had a bedroom upstairs with cable TV."

He added: "Ms Das said when she was sacked 'I will make you regret this for the rest of your life' - and she's lived up to that threat."

Das's lawyer, Paul Grant, said: "There are thousands of people in the UK being kept as modern-day slaves. It is a huge hidden problem happening in towns and suburbs throughout the country.

"Often no one sees these people because they are not allowed to leave the houses and even if they do because they may not speak English no one is aware of their plight."