However, the changed status of the Prison Service, which became an autonomous agency in March last year, has blurred areas of accountability and allowed politicians and civil servants to pass the buck.
The Prime Minister has the final say but for most issues and initiatives the Home Secretary is in charge. Day-to-day operational decisions are made by the Prison Service's director general and a board of 10 directors.
The official rules for the agency, read: "The Home Secretary is accountable to Parliament for the Prison Service. The Home Secretary will not normally become involved in the day-to-day management of the Prison Service but will expect to be consulted by the Director General on the handling of operational matters which could give rise to grave public or parliamentary concern."
Among the issues on which the Home Secretary should be informed are "any incident, issue or other matter which is likely to arouse parliamentary or public concern."
Michael Howard is responsible for all policy changes. and has senior advisers whose job is to keep him informed about all important issues and developments. Mr Howard acknowledged yesterday that he had "ultimate responsibility" for the Prison Service.
Next in command is Michael Forsyth, the prisons minister, who deals with more low-level matters but has closer involvement with the daily running of prisons.
Both ministers are advised by Richard Wilson, the permanent secretary and the most senior Home Office civil servant. Mr Wilson, a grade one civil servant, has been given additional help in the wake of the report into the escape of IRA prisoners at Whitemoor jail to scrutinise the Prison Service's key targets, performance, and business plan.
About once a week he meets Derek Lewis, the director general of the Prison Service, a grade two civil servant, but whose £125,000 salary reflects the business nature of the semi-privatised agency.
Mr Lewis reports to the Home Secretary about once a fortnight. As head of the Prison Service he has responsibility for operational decisions. He does not, however, make policy, he can only make recommendations.
He heads the Prison Service Board, which comprises six members and four non executive directors.
The panel of 10 is similar to a company board. It makes recommendations on policy issues, which are passed on to the Home Secretary, and can make operational decisions. The more controversial and wide ranging ones would normally be passed to the prisons minister and the Home Secretary for their information. The board is made up of career civil servants, two former governors and private business people.
The six full-time staff on the Board include Tony Pearson, director of programmes, and Philippa Drew, director of custody, who also share responsibility for the operational running of jails in England and Wales.
Richard Tilt, director of services, is in charge of over-seeing security. His responsibility for security - he went to the Isle of Wight yesterday - was given to him following the Whitemoor report. The former governor is also involved in the running of catering and buildings.
Dr Rosemary Wool, director of health care, is in charge of inmates' health, medical officers and hospitals. Tony Butler is director of personnel and Brian Landers is director of finances.
The four non executive directors are Sir Duncan Nichol, a director of Bupa and the former head of the NHS, Millie Banerjee, a director of BT, Bill Bentley, a former manager at BP, and Geoffrey Keeys, a director of the Prudential insurance company.
Next in the line of power are the area managers. Each of the 15 managers - almost all are former governors - are responsible for the running of about 10 prisons.
Equally powerful are the 10 heads of division - all career civil servants - who oversee policy. Under these two groups are the 133 governors, who have teams of assistant governors to help them.
On the bottom rung are the prison officers and civil servants who work at the jails, Prison Service and Home Office.