He is one of the world's wealthiest men with a fortune estimated at $23bn (£14bn), yet he drives a 15-year-old car, flies economy class and encourages the thousands of staff in his global empire to use both sides of company notepaper when writing letters.

Ingvar Kamprad, the 84-year-old founder of Ikea, has a legendary reputation for thriftiness, despite being the 11th richest person on the planet. But Swedes have been shocked by recent revelations which suggest that Mr Kamprad may have taken his parsimony a step too far.

It is alleged that he has been secretly running his empire via a Liechtenstein foundation, which is alleged to help Ikea avoid millions in tax. It is perfectly legal.

Mr Kamprad, who now lives in Switzerland, has insisted that he and his family no longer have any control over Ikea. But a television documentary by Sweden's SVT channel alleges that he “secured control and power over Ikea and... created a foundation in one of the world's tax havens — Liechtenstein”.

Mr Kamprad declined to be interviewed for the documentary. However, just before the programme was aired last week, he issued a statement admitting that he still had some control over Ikea via the foundation, whose existence had hitherto been unknown.

In Sweden, the allegations have dented the image of one of the country's best-known companies, which had enjoyed a reputation for scrupulous corporate responsibility.

Belfast Telegraph