The Liberal Democrat’s leader in the House of Lords has been appointed as a minister in the Ministry of Justice.

Lord McNally, who is also the Lib Dem spokesman on constitutional affairs, has been appointed a middle-ranking minister. The 67-year-old peer is a former Labour MP who led prime minister Jim Callaghan’s political unit in the 1970s.

McNally is joined by Conservative MP Nick Herbert, who becomes policing minister, operating from both the MoJ and the Home Office. Herbert was shadow justice secretary from June 2007 to January 2009, when he became shadow secretary of state for environment, food and rural affairs.

Junior ministerial appointments at the MoJ are expected to be announced on Monday.

Meanwhile, Edward Garnier QC, Conservative MP for Harborough in Leicestershire, has been appointed solicitor general.