Inspired both by experience of postings in Calcutta and the American Deep South, and also an uncle who was an active communist, he joined the Communist Party of Great Britain (CPGB) in 1944. After the war, Peck worked in the steel industry and became an active trade unionist. He first stood for election for the CPGB in 1946, taking only 146 votes for the Scunthorpe seat on Lindsey County Council.
In 1948, he moved to Nottingham to take up a full-time post for the CPGB area committee, and in 1955 began regularly contesting the Bulwell ward for Nottingham City Council.
In his election campaigns, Peck often used photographs of himself in his Royal Air Force uniform, wearing his medals, something which proved controversial with other CPGB members. Peck became a well-known figure in Nottingham, and in the 1960 film Saturday Night and Sunday Morning, he is shown speaking to a meeting at the gates of a factory.
He served as first secretary, then president, of the Bulwell Tenants Association, and during the 1970s he was vice-president and president of the Nottingham Trades Council. During the 1980s, Peck served as national election agent to the CPGB, briefly as acting national organiser, and eventually was elected to the CPGB"s executive committee.
However, he increasingly came into conflict with other local members, becoming one of the few supporters of the Eurocommunist leadership in the area.
From 1988 to 1990, with the remainder of the council consisting of an equal number of Labour Party and Conservative Party members, Peck effectively held the casting vote, generally siding with Labour, but voting against them to prevent a reorganisation of council departments. In 1990, with the CPGB on the verge of dissolution, Peck defected to the Green Party of England and Wales, for which he held his seat at three further elections, until he retired in 1997. In total, he contested 49 elections at various levels, a record acknowledged by the Guinness Book of Records.
Peck published an autobiography in 2001, entitled Persistence, while leading the Nottingham Pensioners" Action Group.
He died in 2004 after suffering ill health.