Should any inhabitant of west Oxfordshire happen to look up and see an Airbus flying overhead, resplendent in silver and blue, they should wonder not: it is only their neighbour, Prince Bandar, stopping off at his Oxfordshire pad between Riyadh and Washington.

The Saudi Arabian has landing rights for his private jet, which sports the colours of his favourite American football team, Dallas Cowboys, at RAF Brize Norton - which is handy for his 2,500-acre estate, complete with village and church dating from the 12th century, at Glympton Park.

Prince Bandar bin Sultan is the man who helped facilitate, on behalf of the UK Government, the controversial £43m Al Yamama sale of weapons made by BAE Systems to the undemocratic Saudi Government in 1985, Britain's biggest ever arms deal and the subject of a Serious Fraud Office (SFO) investigation, famously brought to a dramatic stop last year.

In 1990, he bought the Glympton estate, with 39 cottages and 167 acres of parkland, for £11m from disgraced Australian TV and property magnate Alan Bond, who was later jailed for perpetrating Australia's biggest corporate fraud. Then the Prince reputedly spent another £42m on renovating it, putting in a security system, and even a replica English pub inside the mansion.

Prince Bandar is suddenly back in the news because the High Court ruled that the Attorney General was wrong to call off the SFO inquiry into the controversial Al Yamama deal between the Saudi and UK governments. Also last month, Oxford Economics produced a report emphasising the importance of BAE Systems to the British economy.

As the newly-appointed ambassador to Washington DC, Prince Bandar was approached by Mrs Thatcher to help secure the deal, according to a book by the Prince's official British biographer William Simpson, The Prince: The Secret Story of the World's Most Intriguing Royal, Prince Bandar bin Sultan, which was written with the co-operation of the Prince himself - before the allegation was made that £1bn was paid out in commission after the Al Yamama deal.

Intriguing he certainly is, with good friends in surprising places.

Nelson Mandela, for instance, is full of praise for him. Mandela is quoted in the book as describing the Prince as "one of the great peacemakers of our time - an outstanding man - a charming, eloquent and nonetheless humble figure... larger than life and full of fun - for he is a storyteller without equal".

Prince Bandar is a nephew of King Fahd of Saudi Arabia. His father was a former Saudi Defence minister, Prince Sultan. His mother was a servant to his father. He trained as a fighter pilot at RAF Cranwell in Lincolnshire.

In 2006, the SFO was ordered by the Attorney General to call off its investigations into the Saudi deal, which had taken 20 years to complete. But last month the High Court rejected the Government's claims that the inquiry had had to be closed down because "lives were at risk" if Britain ceased to receive information on national security from Saudi Arabia. The judges noted: "We fear for the reputation of the administration of justice if it can be perverted by a threat." They added: "No-one, whether within this country or outside, is entitled to interfere with the course of our justice. The rule of law is nothing if it fails to constrain overweening power."

Also last month the Oxford think-tank Oxford Economics published a report, called The Economic Contribution of BAE Systems to the UK in 2006. It was commissioned by BAE and argues that BAE is of vital importance for Britain's economy.

It notes: "In 2006, BAE directly employed 35,000 people, with a value added (GDP contribution) of £2.4bn, exports of £4.1bn, a contribution to taxes of nearly £500m, and Research and Development (R & D) spending of nearly £900m.

"However, its total economic impact is much greater than this as its activities also support other firms' businesses."

Adrian Cooper, managing director of Oxford Economics, admitted to The Oxford Times that the report was paid for by BAE but added: "That does not mean we are not completely impartial and objective in our approach."

The report added that BAE in 1996 contributed £14.5m in research support funds to universities (which Mr Cooper said could well have included Oxford).

Could British jobs be at risk if the SFO investigation is reopened?

A spokesman for BAE Systems said: "Always remember that the Al Yamama contract was between the UK Government and the Saudi Government.

"Now we are supplying 72 Typhoon aircraft under a new contract - which is signed and sealed, so no jobs could be lost there."

She added that speculation about the longer term was just that: speculation.

Commenting on the report from Oxford Economics, Julian Scopes, head of Government relations at BAE Systems, said: "The report findings underscore the importance of the Government's defence industrial strategy, which aims to secure the UK's long-term ability to maintain the skills and industrial capability to sustain a world-class and globally competitive defence industry."

Closer to home, what would Prince Bandar have to say if the SFO investigation were reopened?

His estate manager, Colonel Peter Browne said: "He certainly would not want to make any statement about it at all."

He added that the estate employs about 30 people, plus temporary staff occasionally.