The colloquial British-English expression Morrison hour denoted an extra hour added to the end of a prison officer’s working day.

This phrase refers to the fact that this extra hour was introduced by the British Labour statesman Herbert Stanley Morrison (1888-1965) when he was serving as Secretary of State for Home Affairs and Home Security from 4^th October 1940 to 23^rd May 1945.

The earliest occurrences of the expression Morrison hour that I have found are as follows, in chronological order:

1-: From a speech made by William John Brown (1894-1960), Member of Parliament for Rugby, in Warwickshire, during a debate on the Criminal Justice (Scotland) Bill which took place in the House of Commons on Thursday 20^th October 1949:

The fact is that much of the reformative and remedial character of prison administration is being hampered and frustrated by the lamentable shortage of staff. That shortage of staff creates evil effects all the way round. The risk of attack is increased in proportion to the deficiency in numbers of staff, and that, again, I think everyone will readily appreciate. But the shorter we are of staff the more difficult it becomes to get more, because the effect of the shortage of staff is to require evening and weekend work on a scale which would not otherwise be necessary. The possible recruit compares the irregularities and interruptions of prison life with what he might have in the factory, and the result is that the shorter we are of staff the more difficult it becomes to get more staff. That is the situation today.
Staffs in Scotland and in England are working what is called the “Morrison hour.” During the war they voluntarily offered—and I think it is to their credit—to work an extra hour a day in order to enable the existing inadequate staff to be spread, as it were, a little wider. They are still working that “Morrison hour” today. But even though they are working an hour a day longer than their hours as laid down, there is still a very heavy shortage of staff in both Scotland and England. That complicates every problem of prison administration.

2-: From the Liverpool Echo (Liverpool, Lancashire, England) of Monday 25^th February 1952:

A picture of the restrictions and difficulties gaol warders face daily was given by Mr. L. C. White, the Prison Officers’ Association’s adviser when he presented a claim for increased pay to the Civil Service Arbitration Tribunal in London, to-day.
This is what he said about a prison officer:—
[…]
Permanent overtime of an hour daily was being worked in all male establishments excepting Wakefield, the two corrective centres at Chelmsford and Sherwood, and at Borstal institutions.
An extra hour introduced during the war by Mr. Herbert Morrison, known as the “Morrison Hour,” permitted prisoners to remain out of their cells for a further hour instead of being locked up at 4.30 p.m.. a state of affairs which had caused considerable criticism.

3 & 4-: From speeches made by Victor Yates (1900-1969), Member of Parliament for Birmingham Ladywood, in Warwickshire, during debates on prisons which took place in the House of Commons:

3-: On Monday 2^nd March 1953:

To establish a three-shift system in the prisons requires an increase of 500 officers, and that is the only means by which overtime can be reduced. For 25 years before I came to this House I was employed by one of the most efficient firms in the land, who always said that overtime was a great evil, to management as well as to workers. Yet in 1940 my right hon. Friend the Member for Lewisham, South (Mr. H. Morrison) had agreed, in conditions of war, to every officer working an additional hour, which was called the “Morrison hour.” I am sure he never visualised that that would last for 10 years. Then there were only half the present number of prisoners. According to the Select Committee, it was expected that overtime pay alone would increase by more than £315,000. If the Government would permit the prisons to be adequately staffed they would be able to save a considerable sum of money, because they would abolish overtime, and they would get greater value for the work that was being done.

4-: On Friday 5^th February 1954:

I called attention to the fact that the expense of overtime last year was £350,000, and the prison officers are still working it. That has continued from the time that the “Morrison hour” was introduced, and there seems to be no chance or hope of its being changed in the near future. When my right hon. Friend the Member for Lewisham, South (Mr. H. Morrison), was Home Secretary, he committed the prisons to working an additional hour, which was known as the “Morrison hour” and it has not been changed. The officers are still working it.

The abolition of the Morrison hour was announced as follows in The Birmingham Post (Birmingham, Warwickshire, England) of Thursday 19^th May 1966:

80-hour win for prison officers

The Prison Department intervened yesterday in the Prison Officers’ Association conference and said they had agreed to an 80-hour fortnight and had abolished the “Morrison hour” of compulsory overtime each day.
Mr. Fred Castell, general secretary, told the conference the Prison Department had phoned him at Plymouth.
He said: “They have agreed to the 80-hour fortnight with effect from June 6. The “Morrison hour” has also been abolished.”
The “Morrison hour” was introduced during the war by the then Home Secretary. Prison officers were paid for this extra hour.
This meant the “Morrison hour” had been abolished in Monday to Friday working. It did not mean the introduction of a five-day week which was still being negotiated.
Mr. Castell described the new position for prison officers as a “major breakthrough.”