An extremely rare meteorological phenomenon has been caught on camera in north Norfolk.

A photograph, captured by Niels Thomas, shows a vessel appearing to hover above the sea off the coast of Cromer. 

This bizarre optical illusion is known as a superior mirage which happens when the air below the line of sight is cooler than the air above it. 

The temperature inversion makes it seem as though an object is hovering above the horizon. 

READ MORE: Kelvin-Helmholtz cloud seen over the sea at Trimingham

Mr Thomas, who works for the National Coastwatch Institution, witnessed the phenomenon on Thursday (August 10). 

He was taking a walk along the seafront when he noticed the 'hovering' ship. 

The 70-year-old said: "I go for a coastal walk every day and in the last three years I've been living in Cromer I've only seen it twice.

"Normally, air temperature gets cooler with altitude but in the case of the phenomenon depicted in this photo cool air from the North Sea is sitting below a layer of warm air.

"Because the light coming from the vessel is passing through cold air, it makes the vessel appear to be higher on the horizon than it is.

"It's very rare to see."