At Wattisham the taxiway from the Q Shed to the runway entered the runway with only 6000 ft of runway remaining. We had certain headwind requirements to takeoff in QRA fit without a backtrack. As a 1st tourist I thought that it would be a good idea to light the burners early. The access has about 60 degree turn to line-up. I lit the burners as I started the turn (since they took 3-5 secs to light). Imagine my surprise as 32,000 of thrust pushed my 25 tonne ac towards the grass. Thank god for MacD and the strength of the undercarriage. There is little doubt that in most other ac I would have broken the gear or gone into the grass in spectacular fashion.