At the same time, Castle was trying to roll back the power of the Trade Unions.
She outlined her proposals in a White Paper, In Place of Strife. Amongst other measures, it suggested a ballot was needed before strike action was taken.
There was a bruising row in cabinet and Castle’s plans collapsed, and Hattersley moved to the Ministry of Defence.
In 1969, he was required to sign the order that sent British troops into Northern Ireland – while his boss, Denis Healey, recovered from a trip to hospital.
Hattersley also disbanded the B Specials, the controversial reserve police force, replacing it with the Ulster Defence Regiment.
In the 1970 general election, he held his seat but Labour was out of office and he spent all but five of the next 27 years in opposition.
Hattersley was appointed shadow spokesman on foreign affairs, and became a keen supporter of the Common Market.
And he was one of 69 Labour MPs who voted, with the Conservative government, in favour of British entry – an issue that would split the Labour Party for the next two decades.
