The Department of Health has confirmed Baroness Thornton as its latest health minister.

The appointment ends a six month wait to replace Lord Darzi in the role of parliamentary under-secretary of state for health. Baroness Thornton was already a government health spokeswoman in the House of Lords and a government whip.

She was one of nine peers cleared of wrongdoing over expense claims earlier this month by the Clerk of Parliaments, Michael Pownall.

She has claimed up to £22,000 a year since 2002 by classifying her mother’s bungalow in Bradford as her main residence, despite owning a family home in London. Mr Pownall ruled that peers only have to spend one night a month in their “main residence” to qualify for expenses.

A former general secretary of the Fabian Society, Baroness Thornton introduced a private member’s bill in 2007 to end television advertising for high fat, salt and sugar foods before 9pm.

The Liberal Democrats last week sacked their health spokeswoman in the House of Lords, following comments she made about alleged organ trafficking in Haiti.

Jenny Tongue told the Jewish Chronicle there should be an inquiry into claims made in the Palestine Telegraph that Israeli troops sent there after the earthquake were trafficking organs.

Liberal Democrat leader Nick Clegg released a statement on Friday in which he said her comments were “highly offensive”.

“The comments were wrong, distasteful and provocative and I recognise the deep and understandable distress they have caused to the Jewish community,” he said.