A historic chimney is set for demolition at Sellafield.
The Primary Separation Plant Chimney Stack was built in the 1950s to provide ventilation for surrounding buildings.
It is now one of the biggest risks at Sellafield because it does not meet modern safety standards.
Demolishing a 61-metre chimney in the middle of Europe's most complex, congested nuclear site is a challenge.
Explosives are not an option and there is no space for a crane so engineers have spent the last seven months getting a self-climbing platform to the top of the chimney metre by metre so they can begin demolition:
ITV Border was given exclusive access to the newly installed platform at the top of the chimney more than 100 metres above Sellafield.
Later this year hydraulic machinery will be used to "nibble" the chimney away at a rate of one metre a week.
The work is due to be finished by 2020 and its final height will be nine metres.
The chimney is surrounded by nuclear buildings so it is crucial that no equipment or debris falls to the ground:
Demolishing this chimney will cost more than £60m.
The Nuclear Decommissioning Authority which oversees Sellafield says the complexity of this one project demonstrates why cleaning up this site is so expensive.
£2bn was spent at Sellafield last year alone.
The MPs who monitor government spending say they are keeping a close eye on the budget: