Georgia Brown, from Aldershot, Hampshire, astounded experts by scoring 152 in an IQ test - putting her in the top 2% of the population for her age.

Psychologist Joan Freeman, who tested Georgia, said she thought the toddler could have scored even higher but needed a nap after 45 minutes of work.

Georgia's mother, Lucy, said: "It's fantastic. We're so proud as a family."

I had come unexpectedly into the presence of something rather special

Prof Joan Freeman

She had spotted that her daughter was a strikingly quick learner.

Georgia was crawling at five months, walking at nine months and, by 18 months, was having proper conversations.

The Brown family called in Prof Freeman, from Middlesex University, to test her IQ level in relation to others of her age.

Prof Freeman said she used the Stanford-Binet Intelligence Scale test and was "elated" by what she found.

She told the BBC: "She is two years, nine months - not very much older than a toddler really - and she is able to answer questions five and six-year-olds can't.

"The test uses questions like 'If brother is to boy, then sister is to ...?'. If you take a normal two-year-old, they cannot hold a pencil, they don't know the colours and they would not be able to answer those simple questions.

'Amazing' concentration

"The thing I found most striking was the copying of a circle. Most two-year-olds cannot do that but she drew a perfect one.

"I was quite elated - I had come unexpectedly into the presence of something rather special.

"She scored 152 points but I think she could have got more - she just got very tired. Concentrating for three-quarters-of-an-hour at that young age is amazing."

Mensa confirmed Georgia was their youngest member at the moment and the youngest female member ever.

The youngest ever member was a boy, who was several days younger than Georgia when he joined in the 1990s.