The huge new gas plant which will service the vast West of Shetland region contains almost one fifth of the UK’s remaining oil and gas reserves and will produce Around 90,000 barrels of oil equivalent every day.

It will be pumped through the new Shetland Gas Terminal before being sent to the mainland through Sullom Voe.

Work on the £800 million terminal, part of a £3.5 billion investment by French company Total, started in 2010 but it was hit by a series of delays which developer Petrofac blamed on bad weather and industrial action.

The Laggan and Tormore fields are on the edge of the UK continental shelf, where water depths descend rapidly from an average of 120m to 600m and beyond.

Total said: “It’s a uniquely challenging environment in which to operate, but also one with great potential.”

The Shetland Gas Plant construction phase was estimated to have involved up to 800 jobs, with 70 full time posts in plant operation.

It has been built on a peat bog next to the Sullom Voe oil terminal.

As well as the onshore construction, there was a major programme of subsea infrastructure and pipelines.

From Shetland, a pipeline takes the gas back to the UK mainland and into the national gas grid - it is expected to provide about 8 per cent of the UK’s gas needs, supplying more than 2 million homes.