A 330-tonne roof has been fitted on what is claimed will be Europe’s largest shale gas storage tank.

Located at the petrochemical plant in Grangemouth, it is designed to hold more than 60,000 cubic metres of shale gas.

It has a displacement volume of more than 108,000 cubic metres, which means 560 double-decker buses could fit inside the tank.

The project is part of INEOS’ £450 million investment package to equip the site to import shale gas from the US.

It plans to ship 40,000 barrels of gas every day – or 800,000 tonnes per annum – for 15 years.

Last year INEOS announced plans to invest up to $1 billion (£640m) in shale gas exploration in the UK.

John McNally, CEO of INEOS O&P UK said: “This is a landmark day for Grangemouth. We know that US ethane has transformed US manufacturing and now Scottish industry will benefit as well. This will secure an essential supply of ethane for the next 15 years as the North Sea declines.”

The company expects the first US ethane to arrive in Grangemouth during the second half of 2016.