Three Labour MPs and one Conservative peer will face criminal charges over their expenses.
David Chaytor became Labour MP for Bury North in Labour's landslide 1997 election victory, after making unsuccessful attempts to get elected in Calder Valley at the 1987 and 1992 general elections.
The former lecturer, 60, carved himself a niche as a backbench expert on education and is an environmental activist. He is also interested in international development in countries including Albania, Cameroon, France, Kazakhstan, Kyrgyzstan and the US.
He is secretary of the Commons Intelligent Energy group, vice-chair of the Albania group and secretary of the Global Security and Non-Proliferation groups.
He has been suspended from the Parliamentary Labour Party and barred from standing again as a Labour candidate.
He is accused of dishonestly claiming £1,950 for IT services and also £18,000 in rent but has said he will deny the charges and defend his position robustly.
Elliot Morley was first elected to Parliament in 1987, winning Glanford and Scunthorpe from the Conservatives in one of only 10 Labour gains in England that year.
The 58-year-old Liverpudlian has a longstanding commitment to green issues and animal welfare and served as fisheries minister and minister for the countryside, handling such issues as foxhunting, EU fishing quotas and the 2001 foot-and-mouth outbreak.
He was in the same department from Labour's election victory in 1997 until his ministerial career came to an end in the 2006 reshuffle, first at the old Ministry of Agriculture, Fisheries and Food - and later at the Department for Environment, Food and Rural Affairs which absorbed it.
His final ministerial job was climate change minister and he continued to serve as Prime Minister Gordon Brown's climate change envoy until the expenses revelations surfaced.
He has been suspended from the Parliamentary Labour Party and was barred from standing again as a Labour candidate.
He faces two criminal charges over £30,000 of mortgage interest claims but has said he will deny them and defend his position robustly.
Jim Devine was elected Labour MP for Livingston, West Lothian, in a September 2005 by-election caused by the death of former Foreign Secretary Robin Cook.
A former Unison union official and psychiatric nurse, he was Mr Cook's election agent between 1983 and 2005 and held several key positions in the Labour Party in Scotland.
He was a junior aide to Health Minister Rosie Winterton between 2006 and 2007 and became chairman of the all-party parliamentary group on Land Maintenance in 2008 and sits on the Scottish Affairs Committee.
The 57-year-old, who was born and brought up in Blackburn, West Lothian, has asked Commons questions on the minimum wage, departmental property, child support and apprenticeships among other issues.
He has also been barred from standing again as a Labour candidate.
He is accused of claiming £3,240 for cleaning services and £5,505 for stationery but denies the charges.
Paul White, Baron Hanningfield, has been a member of Essex County Council since 1970 but has stood down as its leader after being told he faces charges over his Parliamentary expenses.
He was made a life peer in 1998 after a long career in further education, which saw him serve as chairman of the Council of Local Education Authorities and the Eastern Region Further Education Funding Council. Between 1997 and 2001 he was deputy chair and Conservative group leader of the Local Government Association.
Last year, he was given an award by the Countryside Alliance, which said he had done much to highlight and safeguard the future of Essex's rural communities. He has campaigned to save the Post Office network and to protect rural communities.
He has resigned as shadow business spokesman in the House of Lords and has had the Conservative whip withdrawn.
He faces six charges of dishonestly submitting expense claims. He has denied the charges and said he would "vigorously" defend himself against them.