Lois Franxhi, 29, of Winsford, Cheshire, was dismissed from her �20,000-a-year job last July after her employers found she had used the Net during working time.

In the first case of its kind, an industrial tribunal in Liverpool agreed she was guilty of misconduct and supported the firm's decision.

"I found she had been using her computer to do nearly 150 searches on the Internet for personal reasons when she should have been working," said her ex-employer Stephen Jones, a director of Focus Management Consultants, Alderley Edge, Cheshire.

"She said she had only used the Internet on one single lunchtime, but I had proof documenting searches on four different days," he said.

Mrs Franxhi had claimed she lost her job because she was pregnant.

She said Mr Jones had known she was using the Net, but his attitude changed when she told him she was expecting a child.

"The total time I was looking for holidays amounted to 111 minutes over four days," she said.

"That was two full lunch-breaks and the occasional 10-mintue session. It is outrageous and unfair to be sacked for such a small amount of time."

The tribunal dismissed her claims of sex discrimination and unfair dismissal but upheld her claim for breach of contract and awarded Mrs Franxhi a month's pay in lieu of notice.

The decision could affect the 6m people who have access to the Internet at their office.

Employers' organisations urged firms to set clear guidelines for staff in the wake of the ruling.

Stephen Alambritis, of the Federation of Small Businesses, said: "Employment tribunals do not set precedents so another case could go another way.