Born in Middlesex, younger son of Sydney Walker, a capstan operator at HMV's factory at Hayes, and his wife Rose (née Dean),[2][3][4] Walker was privately educated at Latymer Upper School in London.

He fought the Parliamentary seat of Dartford in the general elections of 1955 and 1959, being beaten each time by Labour's Sydney Irving.

Walker was appointed Member of the Order of the British Empire (MBE) in the 1960 Birthday Honours for political services.

Whilst at the Department for Energy he played an important role in the Government's successful opposition to the 1984–85 miners' strike.

Though he had previously been a close ally of Heath's and was generally considered to be on the left of the party, he was nevertheless one of the longest-serving Cabinet members in Thatcher's government, serving during the entirety bar the last six months of her premiership.

For instance, the Thames was declared biologically dead in 1957 but today many species of fish thrive in the river, including wild salmon and trout.

He campaigned determinedly for greater NHS support for St Richard's and the wider hospice movement, which is staffed largely by dedicated volunteers.