Veteran left-wing Labour MP Michael Meacher has died after a short illness, the party said.
The 75-year old former minister, who also served for a long period in the shadow cabinet, died yesterday.
He has represented Oldham since 1970.
Former Labour leader Ed Miliband was among MPs paying tribute to Mr Meacher who he said was "principled, kind, thoughtful and deeply committed to a fairer, more just world".
Green MP Caroline Lucas said Mr Meacher - who served as environment minister for six years under Tony Blair - was a "great politician, championing climate action".
"A really good person, he'll be much missed," she said.
Peter Dean, Mr Meacher's PA and office manager, told the Oldham Evening Chronicle: "We are extremely sad and it has been quite a short illness he has had and we just don't know the details at present.
"He was such a well respected person and we will just try to deal with any problems people in the area have ongoing. We will still try to assist in any way we can.
"We are extremely sad for his family but all of his staff here at his office have worked with him for 20 years so it is almost like a family bereavement for us.
"Our office usually deals with around 5,000 cases every year so he has impacted on an enormous amount of people's lives."