Chris Fraser has to raise $3bn to complete a tunnel from the polyhalite mine to the coast

In a few years from now, Chris Fraser could be one of the most popular men in Yorkshire — provided his outlandish project goes to plan. The 43-year-old is the driving force behind Sirius Minerals, which is digging the biggest mine seen in Britain for decades to tap a rich form of potash-based fertiliser beneath the North York Moors national park.

When the company starts extracting polyhalite in 2021, Fraser will begin signing fat royalty cheques. Local landowners such as the Crown Estate and the Duchy of Lancaster are in line to pocket $4.9bn (£3.5bn) over five decades.

For an area whose economic decline is exemplified by the faded Victorian splendour of Scarborough, it is a colossal influx of cash. Fraser, a bluff former banker