Pictures of Samantha Burke showing off her baby bump have appeared on the internet. The part-time model, who is seven months’ pregnant, looks happy and excited. As well she might do. For the 24-year-old American is believed to be demanding nearly £90,000 a year from the baby’s father, British actor Jude Law - £6,000-a-month child maintenance and £1,200 a month for rent and bills.

The pair met in Manhattan last Christmas while Law was filming Sherlock Holmes. Friends of the actor claim the relationship was nothing more than a “two-night stand”.

Law, who already has three children by his ex-wife, Sadie Frost, is said to be shocked and worried at the news of Miss Burke’s pregnancy. “He’s terrified that she wants a huge slice of his fortune,” said one source. “He wants to be there for the kid, and obviously he wants to support it and give it a great lifestyle. But he certainly doesn’t want a fling to end up costing him millions. It is a huge worry that she has already got a lawyer involved.”

Although the actor has a reputed £10 million fortune, his fling with Miss Burke looks set to cost him dearly. Had he not been single at the time, there would possibly have been an even higher price to pay – his marriage.

There are many men who throw caution to the wind at the sight of a good pair of legs, but embarking on a casual affair can be disastrous emotionally and, if the woman becomes pregnant, financially too. High powered men are a magnet for a certain type of woman – I have previously dubbed her the “office piranha” – and even the canniest businessman can be pretty dumb when it comes to a pretty face.

Such men often have substantial egos and believe they can get away with a “bit on the side” without there being any lasting consequences, especially if they are away from home at a business conference. That is rarely the case, however.

Jumping into bed with someone in the heat of the moment is never wise, but doing so without using effective contraception is foolish in the extreme. However thrilling the sex, it won’t be worth the risk of having to pay out substantial maintenance payments, school fees and the provision of a house and a car for the next two decades.