Advertising guru Sir Martin Sorrell left a 16-year-old to pay a £1 fine and 21p postage for her rejection letter when it was posted without a stamp.

Sophie Swingewood, a pupil at Clitheroe Royal Grammar School's sixth form, is trying to raise £2,000 to travel to a two-week conference of youth leaders in America.

Now the student, from Waddington, is asking businesses to come forward to ensure she reaches her target for the trip next summer.

Head Judith Evans said she wanted to support Sophie by encouraging other businessmen to be "more generous" and "less careless."

Mrs Evans also revealed she will not be going to Sir Martin, who founded the WPP ad empire, for sponsorship in the future.

She said: "We are currently looking for sponsorship to get language college status. Although I don't want to be seen discouraging sponsors I doubt we will be asking him again. We will probably stay more local.

"It is often that people are refused. Sponsors work in different ways and can't always accommodate. But never have students had to pay to be rejected before. But these things happen. It is just a mistake."

A spokesman for Sir Martin apologised and confirmed Sophie would receive a full refund.