the Paras are the only force in the world to use the so-called Low Level Parachute (LLP), which allows them to jump at just 450ft from the C-130J Hercules aircraft.
The Specification for the LLP originally required a minimum drop height of 250 ft AGL at max AUW.
Towards the end of its trials at Boscombe someone came up with the idea of conducting a live drop at that height. The problem was, that whilst the test team were confident that the parachute would be OK 250 ft AGL was way below the minimum drop height for the (then) current reserve parachute. To de-risk the drop it was decided to carry it out over a French lake with some of the team deciding not to bother with the useless reserve, making it the first (non emergency) British Military parachute descent without a reserve since 1956. Once the trial was all planned it was quite comical the number of phone calls the team received from senior officers trying to pull rank so that they could be on the drop, only to be told that "we have all the Sergeant PJI's we need thank you". In the end the drop was a touch higher than 250 ft as there was some concern that the Hercs rad alt was reading the bottom of the lake and not the water surface. However, the time in the air for the jumpers from leaving the step to landing in the water under a fully inflated LLP was around 9 seconds.