The researchers at the university's Institute of Applied Health Research concluded that their evidence, published in the British Journal of General Practice, showed that annually 32,500 children undergo needless tonsillectomies at a cost to the NHS of more than 48 million US dollars.
"That is something parents can be reassured with that if you choose not to have your child's tonsils out, nothing awful is going to happen".
According to researchers, about 37,000 tonsillectomies were performed on children in England by the NHS between April 2016 and March 2017, carrying a bill of £42m.
According to the researchers, unnecessary tonsillectomies were costing the NHS across the United Kingdom £36.9million each year.
Researchers analysed the electronic medical records of over 1.6 million children from more than 700 United Kingdom general practices dating between 2005 and 2016.
Prof Marshall said that while a tonsillectomy might be justified for those most severely affected, "research suggests children with fewer sore throats don't benefit enough to justify surgery, because the sore throats tend to go away anyway".
However, others say the operation offers many children and adults relief from episodes of acute tonsillitis, and that reductions in the use of the procedure have been accompanied by a rise in complications from the condition. In total, data from more than 1.6 million children was considered.
Should you be having your child's tonsils removed just yet? However the team discovered few of the youngsters had been recorded as having clear signs that the operation was necessary. They found that of 15,764 children who had records showing sufficient sore throats to undergo a tonsillectomy, just 2,144 (13.6 percent) actually went on to have the operation.
"The main reason for taking your tonsils out is because of frequent sore throats", he said.
They found that out of more than 18,000 children who had had their tonsils removed during this time, only 2,144 (about 12%) had had enough sore throats to justify surgery.
Marshall said that was not such a big concern.
Thousands of children are having their tonsils removed unnecessarily, costing the NHS millions of pounds each year, according to experts.
Professor Tom Marshall has said that "nothing bad is going to happen" if children do not get their tonsils removed, after a report found that thousands of children are having "unnecessary" surgery. Marshall also noted that 2-4% of children are readmitted to hospital after the operation, typically with bleeding, while about one child a year in the United Kingdom dies from the procedure.
Other reasons for children undergoing tonsil removal included obstructive sleep apnoea and other sleep disordered breathing.
Researchers said decisions to operate on children were "ethically dubious" and wasting the NHS £40m a year.