Five teenagers were able to illegally buy blades in Somerset as part of an undercover sting carried out by Trading Standards officials.
It is the first time that Somerset County Council’s Trading Standards team has carried out test sales of knives on shops and market stalls.
Five underage and undercover teenagers were able to buy illegal blades when random checks were carried out.
One 15-year-old girl paid £25 for a two-handed axe at a market. Hunting and carving knives were also bought.
Five other traders refused to sell blades to the three 15 and 16-year-old volunteers.
Cabinet member David Hall said: “The law is clear about the sale of knives to children and it is important that anyone who sells them knows what is expected of them.
“The shops and market stalls which failed their test have been given a warning, but anyone failing a similar test in future could face a severe penalty.”
Traders who failed their tests have also been told by Trading Standards officers that they are likely to be re-tested.