Footage has been released of cracks found inside a reactor at a nuclear plant in Scotland.

The unit at Hunterston B in North Ayrshire has not been operating since the cracks were found to be growing faster than expected.

A planned inspection of the graphite bricks that make up the core of reactor three in March last year uncovered new “keyway root cracks”.

EDF Energy said these have now grown to an average of 2mm wide.

The firm has released footage of the cracks, which was taken in 2017 and 2018.

Station director Colin Weir told BBC Scotland: “Nuclear safety is our overriding priority and reactor three has been off for the year so that we can do further inspections.

Crack in the reactor One of the cracks found in the Hunterston B reactor (EDF Energy/PA)

“We’ve carried out one of our biggest ever inspection campaigns on reactor three, we’ve renewed our modelling, we’ve done experiments and tests and we’ve analysed all the data from this to produce our safety case that we will submit to the Office for Nuclear Regulation.

“We have to demonstrate that the reactor will always shut down and that it will shut down in an extreme seismic event.”