Gibson was a member of the executive of the Manufacturing, Science and Financetrade union for twenty four years from 1972, and joined the Labour Party as late as 1983 after seven years in the Socialist Workers Party. He unsuccessfully contested Norwich North at the 1992 General Election where he was defeated by the sitting Conservative MP Patrick Thompson by just 266 votes. He was elected to the House of Commons at the 1997 General Election, Thompson had retired and Gibson beat the new Tory candidate by 9,470, and remained the MP there until his resignation in 2009. He made his maiden speech on 17 June 1997. He was the coach of the cross-party parliamentary football team. He was most recently a member of the Select Committee on Innovation Universities Science and skills. He was a member of the science and technologyselect committee from his election in 1997 and served as its chairman between 2001–5. He was chair of the All Party Parliamentary Group on Cancer. Whilst he was the dean of biology at the University of East Anglia he was the head of a research team investigating cancer, and has been awarded a 'Champion' award by Macmillan Cancer Relief for his work in support of people with cancer. He was a major campaigner against top-up fees for universities. He suffered a minor stroke on a visit to Ramallah, West Bankin September 2004. He attracted controversy in August 2006 after claiming inbreeding in his constituency may have played a part in its rising number of diabetes cases. However, he did later apologise for these remarks, stating he did not mean to cause offence. Also in 2006 he took part in a BBC television Inside Out programme, Clouds of Secrecy. The programme reported on the high incidence of oesophageal cancer in the Norfolk area and the possible link with secret experiments carried out in the 1960s, when the Ministry of Defence sprayed quantities of the poisonous chemical zinc cadmium sulphide into the air above Norfolk. Dr Gibson expressed the hope that further research might take place to establish whether there was indeed a link between these tests and the high local rates of cancer of the oesophagus
Expenses controversy
In May 2009, Gibson became embroiled in the MPs' expenses scandal detailed by The Daily Telegraph, who reported that he claimed for a flat in which his daughter lived rent-free before selling it to her for half its market value. Subsequently, he was barred from standing in the next general election by a disciplinary panel of the Labour Party. Believing that after the panel's decision his position was "untenable", he resigned as an MP, thereby forcing a by-election. The resultant by-election was won by Chloe Smith, the Conservative Party candidate, with a majority of 7,348, reversing a previous Labour majority of 5,459.
Personal life
Gibson has been married to Elizabeth Frances Lubbock since March 1974. They have two daughters. He is a supporter of Norwich City F.C.