An advanced police driver has been jailed for five months after crashing his car at more than 120mph in a horror incident described as being like a "speeding missile".
A judge told Sgt Craig Bannister that his behaviour on the M4 near Swansea had put other drivers at "enormous" risk.
Cardiff Crown Court heard that Sgt Bannister, 30, who qualified as a top police driver just a month earlier, had been stood down from an emergency call in his powerful BMW 5 series but had continued to drive at high speeds as he joined the motorway.
Just minutes later, after his speed had topped 120mph, the South Wales Police officer hit a patch of water, forcing him to spin out of control and send his car flying through the air.
Sgt Bannister, of Neath, South Wales, received minor injuries and was found guilty of dangerous driving by a jury last month.
Recorder Peter Murphy QC told him: "You chose to deliberately accelerate, reaching speeds of at least 120mph in the pitch black. You did so for your own ends, and so launched a speeding missile into the unknown, with reckless disregard for other road users.
"The potential risk to other road users was enormous. What you hit was water. It could so easily have been another vehicle."
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