As the TUC called for a rate higher than the £3.60 set by the government, Unison published a "clock" showing how much money is earned in an hour by different groups of workers.

Addressing the TUC conference in Blackpool Unison's leader, Rodney Bickerstaffe said the proposed minimum wage could not be fair.

"It cannot be an acceptable level. It is not enough for food, clothing, rent. Not enough for a night out or to give the kids a treat."

He added: "I believe £3.60 is a retreat from earlier commitments."

Mr Bickerstaffe's remarks follow those made on Monday by the TUC president John Edmonds when he provoked controvery by describing boardroom 'fat cats' as "greedy bastards".

Hourly earnings breakdown

• Five minutes: A director of Rentokil earns £49.25.

• Ten minutes: Catering assistant in a private nursing home earns 37p.

• Fifteen minutes: A director of British Gas earns £56.

• Twenty minutes: Senior porter at a university earns £1.40.

  Twenty-five minutes: Powergen director earns £83.

• Thirty minutes: Clerical worker in a private nursing home earns £1.50.

• Thirty-five minutes: A director at United Utilities will gross £107.

• Forty minutes: Qualified nurse in a residential home earns £3.37.

• Forty-five minutes: A National Grid director takes home £121.

• Fifty minutes: Care assistant earns £2.25.

• Fifty-five minutes: Director of Westminster Health Nursing Homes earns £103.