Lake Pickering was an extensive proglacial lake of the Devensian glacial. It filled the Vale of Pickering between the North York Moors and the Yorkshire Wolds, when the (largely Scandinavian) ice blocked the drainage, which had flowed north-eastwards past the site of Filey towards the Northern North Sea basin. The lake surface rose until it overflowed southwards and cut an exit between the Howardian Hills and the Yorkshire Wolds at Kirkham Priory between Malton and Stamford Bridge, so creating the River Derwent.
In modern times, as an artificial flood relief channel, much of the flow of the River Derwent (which drains a large area of the North York Moors) has been diverted, about 6 miles (10 km) upstream of West Ayton, before it reaches the plain of the Vale of Pickering, east into a new channel called the Sea Cut along a previously dry side valley (probably a glacial overflow channel) and into the existing Scalby Beck's course through Scalby, North Yorkshire to the North Sea.
The idea of these lakes was first proposed in 1902,when Professor Percy Kendall of Leeds University published a paper detailing his theories.[1] It has been suggested that lake Pickering was the largest inland lake in Britain at the end of the last Ice Age.[2]