England and Wales have about 2,000 dams and there are around 800 in Scotland. These structures were built for a variety of reasons: to make reservoirs that can supply drinking water to nearby towns and cities; to fill local canals; to help farms; and to create places for fishing, sailing and water sports.

In the case of Toddbrook’s dam, it was built in the 1830s to create a reservoir that would provide water for the local canal system. It is still owned by the Canal & River Trust.

All UK reservoirs with a capacity above 25,000 cubic metres must comply with the Reservoirs Act and a civil engineer has to file an annual safety report to the Department for Environment, Food and Rural Affairs (Defra). The Canal & River Trust said the annual inspection of Toddbrook Reservoir in November indicated that the dam was “absolutely fine”.

A trust spokesperson added that the reservoir is also inspected twice a week and it was during the most recent visit that the problems affecting Toddbrook were revealed.

Professor Nigel Wright, a civil engineer and expert in flood risk management, told the BBC yesterday that the last evacuation associated with dam problems in the UK occurred in 2007, when cracks appeared in the dam at Ulley Reservoir, near Rotherham, following heavy rain. A new spillway was later built to replace the original which collapsed during the floods.

“Since then, the government has insisted that a lot of dams have been reanalysed to check what the danger is and come up with plans for evacuation if necessary,” added Wright, who is based at Nottingham Trent University.