text: Colour Sgt Martyn Horton, L/Cpl David Ramsden, Pte Douglas Halliday and Pte Alex Isaac all died after the crash in Helmand on 23 June, 2010.
  The collision forced their Ridgeback vehicle onto two wheels, before rolling into the canal, the court heard.
  The inquest is due to take five days.
  The hearing, at Salisbury Coroner's Court, resumed on Monday after being part heard in November,
  The servicemen were members of a police advisory team, travelling as part of a two-vehicle convoy, at the time of the crash.
  The vehicle, driven by L/Cpl Ramsden, collided with an Afghan National Police car by the Nahr-e Bughra canal.
  The inquest heard how the crash happened as the vehicle was travelling to a police checkpoint, at the request of the Afghan National Police.
  The request followed several explosions in the area.
  Dr John Searle, a consultant in accident reconstruction, said: ""It was a glancing impact, an impact where the vehicle carries on and is not stopped by the impact."
  He said visibility in the vehicle would have been similar to a car driving in normal night-time conditions.
  Pte Michael Peers, who managed to escape from the submerged Ridgeback, said the occupants were wearing seatbelts and opened the back hatch near the water, as was recommended.
  "I heard a loud bang which was like an explosion, I do not know where it came from or where it impacted, if it did impact," he said.
  Colour Sergeant Horton, 34, was from Runcorn in Cheshire, L/Cpl Ramsden, 26, was from Leeds and Pte Halliday, 20, was from Wallasey in Merseyside.
  Pte Isaac, 20, was from the Wirral.
  All four soldiers were from the 1st Battalion The Mercian Regiment (Cheshire).
target: An inquest into the deaths of four servicemen in Afghanistan has been told the armoured vehicle they were in rolled into a canal after colliding with an Afghan National Police car.