Ninety-Two Sanctioned, Seventy-Seven Present: Building a Roster That Actually Works
A Metropolitan Police Range has a sanctioned strength of 92 constables. Six posts are vacant, four constables are on a month-long training, three are on sick leave and two are on deputation to another unit. The range must cover, every day, eight static posts with two constables per shift across three shifts; two mobile patrol vehicles with three constables each across three shifts; a women's help desk with one constable per shift; and a custody guard of two constables per shift. Each constable is entitled to one weekly rest day, which current practice honours. The range commander asks the inspector to check whether the deployment is feasible for the coming week and to produce a roster by 18:00. A public festival is expected on the fifth day, which will require four extra constables at two locations for one shift each.
1. Calculate the available strength, the weekly requirement and the shortfall. Show your working.
Read the worked answer
Available now: 92 − 6 (vacant) − 4 (training) − 3 (sick) − 2 (deputation) = 77 constables.
Weekly capacity, honouring one rest day each: 77 × 6 = 462 person-days per week.
Daily requirement:
- Static posts: 8 posts × 2 constables × 3 shifts = 48
- Mobile patrol: 2 vehicles × 3 constables × 3 shifts = 18
- Women's help desk: 1 × 3 shifts = 3
- Custody guard: 2 × 3 shifts = 6
Total = 75 person-days per day, or 75 × 7 = 525 per week.
Festival day: 4 constables × 2 locations × 1 shift = 8 extra person-days, so the week needs 525 + 8 = 533 person-days.
Shortfall: 533 − 462 = 71 person-days, which at six working days per constable is 71 ÷ 6 ≈ 11.8, i.e. about 12 more constables. Put another way, 533 ÷ 6 = 88.8, so 89 available constables would be needed against 77.
The deployment as written is not feasible. The roster must change, the strength must change, or both.
2. Produce a defensible weekly plan within the 462 person-day ceiling, explaining what you cut and why.
Read the worked answer
Prioritise by legal obligation, then risk, then presence.
Non-negotiable: custody guard 6 per day (a detainee left unguarded is a criminal liability and a suicide risk) and the women's help desk 3 per day (statutory policy and the station's only specialist interface with vulnerable complainants). That is 9 per day, 63 per week.
Reduced static posts: 6 of the 8 posts × 2 × 3 = 36 per day. The two posts closed should be the two with the lowest recorded crime and vulnerability in the last quarter - not the two that are inconvenient to visit. The loss is offset by scheduled patrol checks at those points, logged with times.
Patrol: two vehicles for the day and evening shifts (2 vehicles × 2 shifts × 3 = 12) and one vehicle at night (3) = 15 per day.
Total: 36 + 15 + 3 + 6 = 60 per day = 420 per week. Add the festival's 8 person-days = 428, leaving 34 person-days of buffer for unforeseen absence.
The reduction of two static posts is a command decision, so the inspector puts the risk assessment in writing and sends it to the range chief before the roster takes effect. Undocumented cuts become the inspector's personal fault the first time a burglary occurs at a closed post.
3. Should the inspector simply cancel weekly rest days or move everyone to 12-hour shifts for the festival week?
Read the worked answer
No - not as a routine fix, and not on the inspector's own authority.
Legally and administratively: rest days and shift patterns are governed by police regulations and standing orders. Cancelling rest requires the competent authority's order, a written record, and compensatory rest. An inspector who cancels rest unilaterally has taken a decision above his pay grade, and the first grievance will be framed that way.
Operationally: the arithmetic does not require it. The plan leaves a 34 person-day buffer and the festival needs only 8. Fatigue is also a real risk: a constable on a 12-hour night shift at a static post is less alert, more likely to be assaulted, and more likely to use force badly. Long shifts create the incident the roster was meant to prevent.
What to do instead:
- Absorb the festival from the buffer and, if needed, from the two reduced patrols on that day.
- Request the district reserve or defer the training of the four constables if absences rise during the week.
- If overtime is unavoidable, record who worked it and schedule compensatory rest; send a copy to the range chief.
The inspector who solves a two-person problem with a structural change has created a bigger problem for the next month.