The Times, which has a more highly-staffed graphics department than your lowly Jalops, pieced together a graphic illustrating the Hamster's fateful trip down the runway at Elvington Airfield in the Vampire. From everything we know, Hammond didn't crest 300mph, although the Times claims he was "reaching speeds of up to 300mph." Also of note, the Vampire's Rolls-Royce Orpheus engine consumes 7-10 gallons per mile. That's a fair bit of JP-8.
Graphic: Hammond's high-speed crash [Times, UK]
Scene Of The Crash: BBC Video Report On Richard Hammond; Doctors Report "Significant Brain Injury"; Update! BBC Reports Top Gear's Richard Hammond "Improving" After Jet Car Crash; Huzzah! Richard Hammond Now Described In "Stable Condition" After Jet-Car Crash; Update! Richard Hammond "Fighting For His Life" After 280 Mph Jet-Car Crash [Internal]