The author of the Harry Potter books, JK Rowling, has spoken out in support of lone parents, and called for an end to negative stereotyping.

In a speech to mark her appointment as an ambassador for the National Council for One Parent Families (NCOPF), Rowling, a single mother herself, said: "It is definitely time we exploded the popular myth that most of us are feckless teenagers trying to get council flats."

The best-selling children's author has also donated £500,000 to the charity.

Rowling, 34, whose latest volume - Harry Potter and the Goblet of Fire - sold more than 370,000 copies on its first day in the UK alone, is now reckoned to be the richest woman in Britain.

An annual list of top female earners published in the Mail on Sunday in August said she had netted £20.5m over the last year.

'Not all hardship'

But when she began her writing career seven years ago, she was struggling to bring up a baby daughter, Jessica, on £70 social security benefits a week.

Her marriage to a Portuguese journalist had broken down soon after the child was born, and Rowling moved to Edinburgh to be near her sister.

In her speech on Wednesday, she urged the public not to see poverty and single motherhood as inevitable and inseparable facts.

"Six out of 10 families headed by a single parent are living in poverty," she said.

"But none of the lone parents I know want to live on handouts; just like parents living in couples we want the chance to provide properly for our own children."

She added: "Single parenthood is not all stress and hardship. My flesh and blood daughter is the best thing that ever happened to me, including my fictional son."

Although Rowling conceded that her success may be linked to "a certain wizard", she said she would have been lucky anyway in comparison to most or some other single mothers.

She said: "I had a degree, a profession and friends who were willing and able to lend me money when I badly needed it.

"So if I met obstacles in pulling myself out of the benefit system and back into employment, how much more difficult must it be for people who don't have the same advantages?

"If I experienced the feeling of utter, utter worthlessness with the CSA (Child Support Agency) and the benefit office, how many other parents are going through the same right now?"

Ms Rowling said her £500,000 donation to the NCOPF would help it with the establishment of a new website www.oneparentfamilies.org.uk.