Sir – Last year, during a two-month period of unusually warm weather, six people drowned in former quarry lakes across the UK, and warmer weather heralds an increase in young people and adults entering quarries uninvited with potentially tragic consequences, reinforced by two fatalities in quarry lakes and a serious injury following a fall from a quarry rock face this year.

With the start of the school summer holidays, the Mineral Products Association is keen to ensure that the risks are better understood and appeal to parents to ensure that youngsters are not tempted to enter into local quarries uninvited.

Our Stay Safe campaign is supported by parents of teenagers who have died in quarry accidents.

Quarry lakes or other open water like reservoirs may look inviting but the temperature of the water can be icy cold, extremely deep and conceal unexpected hazards such as currents, pumps, weeds or obstacles hidden beneath the water.

The impact that cold water can have on the body can result in even very experienced swimmers suddenly finding themselves in trouble and the water can be difficult to exit.

Other dangers include unstable or concealed cliff edges that could give way, falling rocks, stockpiles that can collapse when children tunnel into them and settling ponds that can act like quicksand.

Quad and trail biking in quarries exposes riders to the risks from unstable ground collapsing or being hit by plant or machinery.

Please view and share our Facebook page Stay Safe Stay Out of Quarries with others.

Our message and the message from the parents of the boys who have been killed is simple: unless you are invited on an organised visit by the quarry operator, please stay safe — stay out of quarries.

Elizabeth Clements, Mineral Products Association, London