A massive 50 metre sinkhole has caused terror and chaos in Shropshire, after it swallowed a canal. Boats were caught up in the incident, with dramatic images revealing a large breach in the canal in the Whitchurch’s Chemistry area.

This is not the first time such a terrifying incident has occurred in the UK. Residents from the Surrey village of Godstone were evacuated from their homes in February, after two sinkholes opened up along the high street. And last December, about 30 homes were evacuated in Merthyr Tydfil after the ground collapsed.

So what causes a sinkhole to appear and should there be reasons for concern? Firstly, it helps to define what exactly a sinkhole is, so there are no misunderstandings. A sinkhole is really just a depression in the surface because the underlying rock has collapsed.

They have different shapes and sizes – some can look like a saucer, while others appear like deep shafts.

There are several reasons why a sinkhole might appear – from geology to human factors. But perhaps the most common cause is a breakdown in the structure of rocks like limestone or chalk. Quite often carbon dioxide in the atmosphere is dissolved in rainwater to form carbonic acid.

This then seeps through the rock and reacts with it, weakening and causing it to break apart.

Human factors can also be to blame for the appearance of a sinkhole, such as a burst underground water pipe.

Dr Andrew Farrant, British Geological Survey regional geologist for south-east England, told the BBC that this was probably one of the likely causes of the Godstone sinkholes.

He said that a burst water main could have caused a sudden influx of water into the sandstone bed and "flushed" weak sand out the way.