Children who are smacked by their parents are more likely to fail their exams and become bullies, new research has found.
Experts are now calling on the strict parenting practice to be banned in England, in line with the law in Scotland and Wales.
Lead author Dr Anja Heilmann, a public health expert at University College London said: 'Our findings corroborate previous evidence that physical punishment has no benefits and is linked to detrimental outcomes for children's development and wellbeing.
'Therefore, our main recommendation is that England and Northern Ireland should follow Scotland and Wales and remove the legal defence of reasonable punishment.'
The report analysed data from nearly 20,000 children born between 2000-2002, and found that one in five had been physically punished in some way, by age ten.
The researchers found that found that children in England who experienced physical punishment at the ages of three, five and seven were 5.7 per cent more likely not to get five GCSE grades A* to C (between nine and four under the new rating system) including English and Maths compared with children who hadn't experienced it.
Similarly, children who experienced physical punishment at all three ages were 40 per cent more likely to engage in risky behaviours towards others such as bullying or having hit, shoved or pushed someone aged 14 and 26 per cent more likely aged 17.
Children who are hit are also 41 per cent more likely to report bullying siblings.
The report analysed data from nearly 20,000 children born between 2000-2002, and found that one in five had been physically punished in some way, by age ten
Striking a child is outlawed in Scotland, Wales and the Republic of Ireland but remains legal in England and Northern Ireland.
Proposals to make physical punishment illegal were recently dropped in Northern Ireland and similar plans were abandoned in England last year.
In both cases, this was due to a lack of Government support for the change.
Worldwide, using physical punishment against children is banned in 70 countries.
There are now calls for England to follow suit.
Labour MP Jess Asato, said: 'This latest report from UCL confirms that physically punishing children does not improve behaviour and is instead linked to a range of poor life outcomes, including ones which cost the state money.
'The Government must act on the recommendations of this report urgently. Scotland and Wales have already shown there is a way forward that works. Now it is time for England to follow.'
Joanna Barrett, Associate Head of Policy at the NSPCC, said: 'It is unacceptable that in England and Northern Ireland the law still allows a parent or carer to physically punish a child in the name of discipline.
'This UCL research shows yet again that physical punishment does not improve children's behaviour and in fact has an adverse impact on their wellbeing and links to poorer outcomes in the future.
'Like is already the case in Scotland and Wales, children in England and Northern Ireland should be afforded the same protection from assault as adults. It's time to change the law and remove the defence of reasonable punishment once and for all.'
However, not all experts agree that physical punishment has a detrimental impact on a child's development.
Writing for the Daily Mail last year, Professor Robert Larzelere, an expert in human development and family science at Oklahoma State University said: 'As a leading child education expert who has dedicated his life to researching smacking, I think banning the punishment would be a mistake.
'In fact, while I may have had 20 years more education than my father-in-law, I've come to the conclusion that his belief that children who don't listen must "feel" is sometimes the right approach.'
He added: 'The aim is to show children that there are consequences for not cooperating with parents' attempts to resolve bad behaviour verbally or, when necessary, with a mild negative consequence.
'In fact, I would say that, when used correctly, smacking can benefit children – and improve their lives in the long-run.
'Study after study has shown that, along with isolation (sending children to their room), smacking is the most effective measure for preventing oppositional defiance – this is the scientific term for bad behaviour.'
