Headquarters Mobile Support Unit
| Headquarters Mobile Support Unit | |
|---|---|
| Active | 1980 - Present |
| Agency | Police Service of Northern Ireland |
| Type | Police tactical unit |
| Role | Counter-terrorism Law enforcement |
| Operations jurisdiction | Northern Ireland |
| Part of | Specialist Operations Branch (C4) |
| Abbreviation | HMSU |
The Headquarters Mobile Support Unit (HMSU) is the police tactical unit of the Police Service of Northern Ireland (PSNI). The HMSU was originally formed in the then Royal Ulster Constabulary (RUC) part of RUC Special Branch and was involved in several controversial shootings during The Troubles.