SCO19 River Thames Hostage Rescue Exercise
The Met's specialist firearms unit, SCO19, undertook a dramatic hostage rescue exercise on the River Thames this weekend. Around 11am on Sunday morning, a tourist sight-seeing boat, complete with mock terrorists - played by 5 police officers - and hostages, was stormed by SCO19 officers. 
The training exercise featured forces from the Met working alongside other agencies such as the London ambulance service and London fire brigade, Port of London Authority, London Coastguard and the Royal National Lifeboat Institution (RNLI). The sharp end of the operation saw Counter Terrorist Specialist Firearms Officers (CTSFO) approach and board the terrorist-held vessel as it travelled along the Thames close to London's Dockland area. The CTSFOs boarded the vessel via rigid hull inflatable boats (RIBs) piloted by the Met's Marine Policing Unit.
The last public display of SCO19's maritime capabilities occurred during the lead up to 2012 London Olympics. In a similar scenario to Sunday's exercise, SCO19 officers boarded a terrorist-held pleasure boat on the Thames. 
More info / further reading:
- 1. Hundreds of armed police stage terror drill on Thames tourist ship
- 2. Royal Marines / Police Thames Exercise
(Elite UK Forces report)