Lydia Sebastian (pictured) scored a maximum 162 in the 150-minute test of mental agility.

A 12-year-old girl has joined the ranks of Mensa after attaining a higher IQ score than those attributed to Albert Einstein and Professor Stephen Hawking.

Lydia Sebastian scored a maximum 162 in the 150-minute test of mental agility.

The minds behind the general theory of relativity and Hawking radiation are estimated to have IQs of 160.

Lydia’s parents only allowed her to sit the test because she had nagged them about it for a year.

They have never pushed her academically and said they were astonished at the result.

Her father Arun, 43, said: ‘We really have done nothing special with her. She’s our only child so we don’t have anyone to compare her with.

‘The only thing I’d say is that she started speaking when she was quite young – about six months. At the time I was a trainee doctor and my wife was studying chemistry and I was away at weekends. She used to say a few words to me on the phone.

‘She also had an early interest in reading. When she was a few years old she was reading books that were for children several years older than her.

‘And maths is her favourite subject. She won a prize for that when she was at primary school.’

He added: ‘We’ve got a fairly laid back view [about education]. If a child is pushed to do something that’s not designed for their age then, personally, I’d feel they they’d be missing out on other things.

‘Even now she comes back from school to sit down and do homework until 8.30 or 9pm.’

Lydia, from Langhma, Essex, completed the Cattell III B paper - which examines language skills, including analogies and definitions, and her grasp of logic – with time to spare when she sat it at Birkbeck College in London over the school holiday.

She had to be accompanied by her grandfather as children are not allowed to attend test centres on their own.

Lydia, from Langhma, Essex, completed the Cattell III B paper - which examines language skills, including analogies and definitions, and her grasp of logic – with time to spare when she sat it at Birkbeck College in London over the school holiday

Lydia, who began playing the violin at four and has read all seven Harry Potter books three times, said she wasn’t sure how she would do and just ‘gave it my best shot’

Lydia is an A-grade student at Colchester County High School in Essex, a selective girls’ school whose alumni include director of BBC radio Helen Boaden and GB Olympic gold medal winning sailor Saskia Clark.

Her favourite subjects include physics and chemistry and she hopes to have a career ‘related to maths’ when she is older.

Her father, a radiologist at Colchester General Hospital, and mother Erika Kottiath(CORR), an associate director at Barclays Bank, who both originally come from Kerala in southern India, said they were shocked when they got the IQ test results on Friday.

The minds of geniuses including Einstein (left) and Stephen Hawking (right) are estimated to have IQs of 160 - less than that of Miss Sebastian

Mr Sebastian added: ‘When I heard she had the maximum possible mark I was overwhelmed and so was my wife. To be honest, I didn’t really believe it.’ Einstein and Hawking’s IQs are generally estimated at 160 as they are not known to have sat tests. The maximum adult score is 161.

Lydia, who began playing the violin at four and has read all seven Harry Potter books three times, said she wasn’t sure how she would do and just ‘gave it my best shot’.

She added: ‘At first I was really nervous but as I started it was much easier than I expected and then I relaxed.’

She has now applied to join Mensa, which has 20,000 members in the UK.