http://www.racecar-engineering.com/news/marussia-suffers-straight-line-testing-crash/
The BBC had a local news crew on site during the testing and reported the following “BBC Cambridgeshire presenter Chris Mann, who witnessed the crash, said the car had completed a circuit when it “suddenly accelerated” into the back of the lorry. From where I was standing it looked like the helmet took the brunt of the impact,” he said. “Strangely, the car suddenly accelerated into the lorry and the car went careering into the side of the loading board.”
This sounds very much like the cars anti stall system engaged at the end of the run. Inexperienced drivers having their first runs in a F1 car can be caught out by this. As they slow to stop the car or make a low speed turn (for example into a garage) they lift off the throttle and let the revs drop. The ECU senses this and sets throttle to around 50% with the car still in first gear resulting in a sudden acceleration such as the one described.