Up to 1,000 swimmers are expected to head to Kinder reservoir in Derbyshire on Sunday in the biggest trespass of the water to date. The turnout will mark the anniversary of a mass trespass that helped establish the principle of the right to roam in the UK. The swim trespass of Kinder reservoir, situated below Kinder Scout where the 1932 protest took place, has become an annual event and is growing rapidly with the boom in wild swimming. The event is now in its third year, and swimmers of all backgrounds are invited to the reservoir, owned by the water company United Utilities, to exercise “the uncontested right to swim in open water”. Kate Rew, the founder of the Outdoor Swimming Society, said: “Because the original Kinder Trespass is widely credited as being the turning point of the right to roam, it just feels like a natural place to gather and communicate the story. “We’ve had such an explosion of swimmers since Covid, there’s an increased awareness of how important this is and I think it’s a lot more urgent, and it’s happening a lot faster than we ever thought it would.” The mass trespass of Kinder Scout on 24 April 1932 involved an estimated 400 people and led to six arrests. It is widely considered to have laid the foundations for the UK’s first national park, the Peak District, and helped pave the way for the establishment of the Pennine Way and other long-distance footpaths. Last year about 400 people took to Kinder reservoir to mark the anniversary, and greater awareness, along with the continued growth in wild swimming, means numbers are expected to be substantially higher this year. Although swimming is banned on the reservoir, there have been no arrests or big issues with security staff at previous trespasses. Access to the reservoir is down a steep and bumpy path so all swimmers are urged to plan their route in order to arrive safely, and to come prepared for cold water temperatures. “We really understand that with the right to swim freely comes the responsibility to do it safely,” said Rew. “It’s just about people understanding the dangers of their particular sport and giving them the credit to make a choice about the risks, rather than putting up signs stopping people completely. “We don’t treat mountain bikers and climbers in that way and we don’t think you should treat swimmers in that way either.” A United Utilities spokesperson said: “We recognise the right to protest, but we have to remind anyone thinking of taking a dip that the reason we don’t allow swimming is because it is very dangerous. “Kinder reservoir is an operational site with deep, cold water and hidden hazards. The reservoir is constantly supplying water for the Stockport area so there are also strong currents below the surface.”