A tooth whitening pen sold in Kent had 100 times the legal levels of hydrogen peroxide in it.

At that levels it could have "serious consequences for a person's health", a trading standards investigation found.

Now a trader has been fined more than £700 in a prosecution brought by Kent County Council's trading standards service.

Businessman Thai Tran, 27 of Broadway, Stratford, London, pleaded guilty at Sevenoaks Magistrates' Court to a total of five charges and was fined £715 and had to pay £629 contribution towards costs.

All White 3000 Ltd trading as Sonic Whitening, where Tran was a director, also received five charges and the same penalty.

The defendant traded out of Royal Victoria Place, in Tunbridge Wells, where one of his products included a tooth whitening pen, which was found to have dangerous levels of hydrogen peroxide after a test purchase.

Tran's pen was found by Trading Standards to have a hydrogen peroxide concentration of 10.9% - 109 times the maximum permitted concentration of 0.1% - and was prosecuted under the Consumer Protection Act (1987).

Mike Hill, Kent County Council cabinet member for customer and communities, said: "Hydrogen peroxide in these products is regulated for a reason and too much can have serious consequences for a person's health.

"This prosecution sends a clear message to unscrupulous traders dealing in these products that we view this as a dangerous practice and we will press for the heaviest fine."

The prosecution is the second success this year for Trading Standards in their battle against illegal tooth whitening products.

In July, Simon Liu, a sole trader based in Oldham, was fined £660 and ordered to pay £2,375 in costs after he was found selling goods on eBay containing hydrogen peroxide 124 times the permitted level.