Manningham-Buller will sit as a non-party-political peer on the crossbenches, meaning that she is not obliged to vote with any party.
She was recommended for a seat in the Lords by the Appointments Commission, an advisory body tasked with finding people of distinction who will bring authority and expertise to the House of Lords.
Dame Elizabeth was the Director General of the Security Service (MI5) from 2002 until her retirement in 2007. She has spent most of her working life in the Service.