A four-year-old who can already add, subtract, draw figures, write in sentences and read advanced books has become one of the youngest members of Mensa.

Heidi Hankins sat an IQ test after nursery teachers said they were struggling to find activities to keep her challenged.

The average IQ score for an adult is 100 but the exceptional youngster achieved a staggering 159 points – just one mark shy of scientist Albert Einstein.

She beat number cruncher Carol Vorderman (154 points) and is only slightly behind Big Bang physicist Stephen Hawking (160 points).

Heidi’s father Matthew, from Winchester, Hants, is hoping she can skip a year when she starts school to ensure she does not become bored.

The Southampton University lecturer, 47, said: “We always thought Heidi was bright because she was reading early. I was curious about her IQ and the results were off the scale.

“I got her the complete set of the Oxford Reading Tree books when she was two and she read through the whole set of 30 in about an hour. It’s what you would expect a seven-year-old to do.”

He said Heidi is a head taller than her classmates, and at 115cm (3ft 10in) more physically resembles an average six-year-old.

Dr Hankins added: “We don’t push Heidi at all. She has taken up everything herself and teaches herself.

“In fact, if we try and tell her to sit down and do something she says ‘no’ and goes off to do her own thing.

“In every other way she is like a typical youngster, who likes to play with other children.

“She is not precocious, she is just a little girl who likes her Barbies and Lego but then you will find her sitting down and reading a book.”

John Stevenage, chief executive of British Mensa, congratulated Heidi’s parents for identifying her “great potential”.

“We wish them well and are pleased that they have chosen to join the Mensa network for support,” he said. “We aim to provide a positive environment for younger members to develop.”