JK Rowling, who grew up in Gloucestershire, named Harry Potter's cruel relatives after Dursley in Gloucestershire, she has finally confirmed.

While it has long been suspected, the author revealed it during some new writing for the Harry Potter fan website Pottermore .

Rowling wrote about why the Dursleys disliked their nephew so much.

JK Rowling
JK Rowling

She said the Dursleys were "reactionary, prejudiced, narrow-minded, ignorant and bigoted; most of my least favourite things".

Petunia Dursley, the sister of Harry's mother Lily, and her husband Vernon take their nephew in when his parents are murdered, raising him alongside their own son Dudley, but making him to live in the cupboard under the stairs.

In the latest piece of writing, which appeared on June 23 - Dudley's birthday - she says their cruel treatment dates back to Petunia's jealousy of her sister Lily's magical abilities when they were growing up, and Vernon's dislike of anything out of the ordinary.

Aerial view of Dursley, Gloucestershire
Aerial view of Dursley, Gloucestershire

"Vernon was apt to despise even people who wore brown shoes with black suits."

She said that when Petunia and Vernon first met Lily's boyfriend James, the couples fell out. Vernon suggestied that wizards live on unemployment benefit, and became cross when James told him of the solid gold his parents had in the wizarding bank Gringotts.

Petunia, Dudley and Vernon Dursley in Harry Potter
Petunia, Dudley and Vernon Dursley in Harry Potter

They never made up and when Lily and James were murdered by Voldemort, Petunia "felt she had no choice" but to take Harry in, but did so grudgingly "and spent the rest of Harry's childhood punishing him for her own choice".

She said Vernon was "a name I never much cared for" and Petunia "the name that I always gave unpleasant female characters in games of make believe I played with my sister, Di, when we were very young".

The surname Dursley, is drawn from the Gloucestershire town and, while she has never been there, she liked the sound of the name for the characters.