Key Points:

Robert Maxwell, corporate kleptomaniac, ruthless bully and possible war criminal, barks orders into a phone.

He was the corrupt tycoon, the glutton who liked nothing better than to order up double helpings from his team of top chefs before clambering aboard his personal helicopter in search of the next bent deal.

When Maxwell mysteriously plunged from his yacht into the Atlantic Ocean 15 years ago, he left debts of £400 million and a trail of intrigue and deception that robbed 30,000 pensioners of their life savings.

She, by contrast, is the diminutive nun contemplating the rosary. Sworn to poverty, celibacy and selflessness, Mother Teresa devoted her life to helping the poorest of the poor, the unfortunates forced to inhabit the world's filthiest slums.

On her death in 1997, the Nobel Laureate had helped 27,000 people die in dignity rather than on the fetid streets of Kolkata. Those working in her name were by then feeding 500,000 families a year and treating 90,000 lepers.

The symbolism of the only known photograph of an extraordinary meeting between the crooked newspaper boss and the Angel of Mercy is almost unbearably heavy.

The nun's crisp, clean white habit glows while in the background glowers Maxwell with his bushy black eyebrows and oil-slicked hair.

Little is recorded of what transpired between these unlikely associates. It is known, however, that their meeting took place at Maxwell's opulent Thames-side apartment during Mother Teresa's 1988 visit to London's Cardboard City.

Needless to say, there are no surviving minutes, only the colour snaps taken by a Daily Mirror photographer well-used to recording his publisher's vanities for the pages of his own newspapers.

For television writer Ian Curteis, the meetings have proved a rich source of inspiration. His account of the conversations form the basis for The Bargain, his first new stage play for 25 years which is now touring Britain. But although the protagonists appear to inhabit entirely different moral universes, the playwright contends they have much in common.

It was Maxwell, he says, who engineered the meeting after launching a newspaper campaign to raise money for Mother Teresa's work helping British homeless.

According to the play, the tycoon was planning to publish a new World Encyclopedia of Religions and sought the saintly signature on the title page.

Hoping to con the naive nun into endorsing his latest money-making scheme, Maxwell boasts that her backing would be "worth three Book Clubs and the Whitbread Prize".

But as the action unfolds, it becomes clear that Mother Teresa has an agenda of her own. In return for the use of her name, she demands a contribution to fund her global network of 150 convents. "She was", says Curteis gleefully, "an even tougher bird than he was".

The meeting develops into a formidable battle of wills, with Maxwell abandoning his oleaginous flattery in favour of his customary bully-boy tactics as the negotiations drag on.

But this is by no means a simple war of good versus evil and The Bargain brings out some surprising parallels. As Maxwell's assistant explains at one point, "He and Mother have a lot in common, you know: their total, ruthless, no-holds-barred commitment to what they believe, of a strength that's awesome."

They also shared a strong belief in the power of money. Curteis first found a mention of the meeting in The Missionary Position - Christopher Hitchens' searing polemic that cast doubt on Mother Teresa's saintliness. The controversial British author claims that her life work was not so much tending the needy as raising millions - often from questionable sources including the Haitian dictator Jean-Claude Duvalier and the disgraced financier Charles Keating, as well as Maxwell.

This, he suggests, helped to fund her empire building, allowing her to spread an extreme and aggressive version of Catholicism across the world.

Curteis' interpretation doesn't go quite as far as branding her, as Hitchens does, the "chair of a missionary multinational", but he does not stray into hagiography. His Mother Teresa is a shrewd operator who is content to accept dirty money "because she can make it clean by what she does with it".

For the most part, his is a jokey debunking of saintliness - showing her as a shrewish operator who likes the odd nip of whisky and who possesses a surprisingly wicked sense of humour.

But there is a serious side to the portrait. At the climax of the play, as Mother Teresa continues to refuse to close the deal, Maxwell threatens her with tabloid exposure in the form of letters to her "spiritual adviser" Father Joseph Neuner.

These highly personal confessions reveal a surprising aspect of the nun, as she admits that she has suffered her own dark night of the soul and struggled with her faith.

"There may be some people who simply don't like to know about that side of Mother Teresa. They prefer to see her, as Maxwell says, as an untouchable icon", says Curteis. "But we are all very human, even the great saints."

There are surprises, too, in the character of Maxwell. He begins the play, in his own words, "a filthy, fat, overweight, greasy capitalist". He ends it that way, too. But Curteis dangles the tantalising prospect of redemption as Mother Teresa forces him to confront his Jewish origins and to come to terms with the death of his mother and much of his family at Auschwitz.

"He was an absolute monster," says Curteis. "But he was a vulnerable monster."

According to the playwright, three years later, when Cap'n Bob was found floating in the ocean, the money he had collected for Mother Teresa from the Daily Mirror appeal remained untouched. While some may balk at Maxwell being endowed with any redeeming features, Curteis is more forgiving. "I like to think that she did have an effect on him, and he on her."

It is not a view shared by Hitchens. His distaste for Maxwell is greater than that he holds for the nun. In The Missionary Position, he writes: "Mr Maxwell inveigled a not-unwilling Mother Teresa into a fund-raising scheme run by his newspaper group and then, it seems ... he made off with the money.

"But Maxwell did succeed in fooling some very experienced and unsentimental people in his day, and although it might be asked how Mother Teresa had time to spare for such a wicked and greedy man, it can still be argued with some degree of plausibility that she was a blameless party to his cynical manipulations."

Many admired the zeal with which Maxwell, an illiterate peasant, escaped the slaughter of the Nazis in his native Ruthenia, to serve with the British Army, build a global empire of business interests and gain the ear of some of the world's most powerful leaders.

It was a drive shared by his saintly counterpart. Mother Teresa challenged the power and complacency of the Catholic establishment to fulfil her calling to help the poor, pushing her meagre 1.2m frame to its limits.

In 2002 she took the first step on the path to sainthood when the Vatican declared that her image had miraculously healed a cancer victim.

The Maxwell name has continued to be enmeshed in controversy. His death not only revealed the depth of his financial wrongdoings, but triggered a flurry of allegations, none of them good. His quasi-state funeral in Jerusalem prompted speculation he met his end at the hands of Mossad agents. Whatever the truth of his final moments, Curteis' play will provide fresh material to intrigue students of the Maxwell legend as much as those of Mother Teresa.

But one thing is for sure - whatever the play comes up with, the truth was probably far stranger than the fiction.