A father and son whose family business sold dangerous teeth-whitening products have been jailed for 18 months.
Merthyr Crown Court heard that John Hargreaves, 69, and his son Matthew, 44, sold the unsafe beauty treatments at shows and shopping centres across the UK, as well as online, netting £3.4 million in the process.
A Trading Standards' investigation later found the dental products had hydrogen peroxide levels up to 110 times more than the legal level.
The pair, from Knutsford in Cheshire, managed to sell the goods for eight years - giving unhappy customers and Trading Standards' officials the slip by folding one company before starting another with a new name and address.
Judge Philip Harris-Jenkins described the family's business - which also saw 71-year-old mother Jean pitch in - as "sophisticated and highly organised".
He said: "You duped the public into purchasing unsafe teeth-whitening products and placed them at risk of serious harm.
"You placed personal greed before public safety."
The court heard that Hargreaves senior had previously been cautioned in 2007 after sales of "too strong" teeth-whitening gel at the Royal Cornwall Show prompted a deluge of complaints.
However, the company director ignored the warning from the authorities and they continued to advertise the product - insisting to customers that it was safe.
Prosecutor Mark Wyeth QC said their business proved extremely lucrative, and saw the defendants enjoy a lavish lifestyle - living in a large Cheshire house and owning seven luxury vehicles, including a Range Rover.
However, when complaints started to mount up, Mr Wyeth said the defendants used a number of tactics to try to "evade Trading Standards and unhappy customers" by starting up new companies.
He added: "Fifty four various addresses were used as prophylactic against complaints.
"They not only defrauded the general public but also the authorities, without any regard for people's safety."
The court heard that one woman, named only as Mrs Hague, suffered chemical burns to her mouth and gums from the Hargreaves' teeth-whitening product.
The pair were caught out following an operation by Powys County Council's trading standards, with undercover officials buying products from the Hargreaves' stall at the Royal Welsh Show in 2013.
Officers found that as well as numerous false claims about the gel, which included "used by leading dentists across Europe", it also contained 11% hydrogen peroxide.
Cosmetic product regulations allow sales of products containing up to 0.1% hydrogen peroxide, and anything higher than 6% is classed as being potentially dangerous to health.
Powys council's Operation Gleam later expanded to include 10 other local authorities who had tried to catch the two men.
They pleaded guilty to participating in a fraudulent business, an offence under the 2006 Fraud Act.
They were each handed 18-month immediate custodial sentences and banned from becoming company directors for 10 years.
The court heard that Mrs Hargreaves also played a role in the family business, albeit in a more administrative role.
She pleaded guilty to the less serious charge of engaging in unfair commercial practice, and was handed a six-month sentence suspended for two years and banned from being a company director for five years.
After sentence was passed she broke down in tears as her husband and son were taken into custody.
Powys council's cabinet member for trading standards John Powell welcomed the outcome.
He said: "We cannot have unsafe products being brought into Powys, which could harm our citizens or visitors, particularly as the Royal Welsh Show is our premier event.
"This result also vindicates our decision to embark on a nationwide investigation, demonstrating the excellent skills that our trading standards team possess."
Clive Jones, the council's professional lead for trading standards and community safety, also praised the officers in the case after they took more than 90 statements and collected 6,000 exhibits.
He added: "We will be working with the General Dental Council (GDC) on future campaigns as this was one of the largest cases ever taken and we need to ensure that such sharp practices are stamped out."
Katie Spears, of the GDC, said: "The GDC continue to work hard to proactively spread the message that tooth whitening is the practice of dentistry and that only registered dental professionals can legally and safely provide such treatment.
"We are particularly proud of the collaborative approach taken here with Powys trading standards to promote patient safety and will continue to work with trading standards and other stakeholders to guard against the promotion of potentially dangerous illegal tooth-whitening practices."