In the eleventh century, Arabic astrologer Al-Biruni observed that Scorpios are 'pleased with themselves', and as Scorpio Dawn Airey (November 15 1960) celebrates her fortieth birthday, she has good reason to feel smug. Recently appointed as Channel 5 controller, she has the backing of its main shareholder, RTL, and a fifty percent budget increase.

Scorpio - symbol of sex, power and secrets - seems to be flavour of the month in the television world. Rival Lorraine Heggessey at BBC1 is four years older but has a birthday one day later (November 16 1956), locking the two women into deadly rivalry in the ratings war. Think Lady Macbeth and the Queen of Spades.

So what advice might the old astrologers give to Airey? Writing about the Scorpio temperament in 1910 astrologer Alan Leo comments: "you are a firm and powerful character, arising from the silent force within. You possess magnetic power, critical perception and ability to judge keenly, but when not fully under control, your character will be rather exacting, jealous and proud".

Airey's fun-loving, frank and cheeky style expresses her provocative Uranus in fiery Leo, and a striking feature in her horoscope is a square aspect of this rebellious planet to her Sun. Uranus rock boats but this could be dangerous for someone with public responsibility. Alan Leo declares: "It is bad for public position, popularity, the good will of the world generally; and causes broken ties of all sorts in business, marriage and friendship", and Charles Carter thunders in 1930, "individualistic to the point of anarchy... (the person) will, by some foolish act, destroy the fruits of his own work... he will perhaps suddenly and without reason go off at a tangent and either abandon or gravely injure the construction he has raised".

All of which sounds worrying for steady Taurean Richard Eyre, director of strategy and content at RTL, especially since he has a Uranus contact with Airey. However, she does have a dose of practical and conventional Capricorn which lets her move into the mainstream when she chooses. Like the goat, this Capricorn ambition could pitch her upward until the influence peaks with the highest possible profile in 2009.

But will she shock everyone and blow out with Uranus before then? A critical period is her astrological mid-life crisis on the Uranus half-cycle, lasting from spring until Christmas 2002. For now, she is running on her lucky Venus-Jupiter conjunction. Carter observes that this "tends to popularity, but appeals to the less thoughtful and serious elements of the population". Sounds-like Channel 5?