As home secretary, Whitelaw adopted a hard-line approach to law and order. He improved police pay and embarked upon a programme of extensive prison building. His four-year tenure in office, however, was generally perceived as a troubled one. His much vaunted "short, sharp shock" policy, whereby convicted young offenders were detained in secure units and subjected to quasi-military discipline won approval from the public but proved expensive to implement. He was home secretary during the six-day Iranian Embassy siege in April–May 1980.