Shops in London are selling knives, alcohol and tobacco to children as young as 13, it has been revealed.
London Trading Standards (LTS) carried out over 2,593 test purchases across the capital over 18 months with child volunteers aged 12 to 17. The results showed the age-restricted items being sold to under-18s.
A total of 285 illegal sales were recorded, with 14% of shops selling knives and 12% selling alcohol. It is illegal to sell these products to anyone under the age of 18.
London Trading Standards said that a majority of shops refused to sell to underage customers but it was "disappointed" that underage sales were taking place, while the Met Police said it was "unacceptable".
The campaign week, which runs through to September 14, seeks to raise awareness of consumer protection issues.
Metropolitan Police Detective Superintendent Sean Yates said: "Knife crime devastates families and communities.
"Tackling knife and gang crime is one of the Met's top priorities, and we are working closely with Trading Standards, the Mayor's Office for Policing and Crime and retailers to do everything we can to prevent young people getting hold of knives in the first place.
"We are also targeting those who carry weapons and cracking down on online videos that glamorise and encourage this terrible violence.
"Everyone has a part to play in ending the deeply concerning rise in knife crime that we have seen across the capital and to spread the message that carrying a knife is more likely to ruin your life than save it."
Trish Burls of LTS said: "We are disappointed that a 13-year-old has been allowed to buy a knife in a London shop but we note the relatively high levels of compliance among the majority of retailers."
She urged retailers to continue to sign up to Responsible Retailer Schemes and said that information about shops making such illegal sales could be reported to LTS.
Sophie Linden, Deputy Mayor for Policing and Crime, said that pushing the courts to review sentences given to retailers who fail to comply with the law was among the efforts being used to try and crack down on traders who illegally sell knives.