Police are monitoring the activities of a shop in Wakefield after its staff sold a large kitchen knife to two teenage cadets.
The illegal sale took place when a test purchase operation was carried out across the Wakefield district.
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Police cadets aged 13 and 16 visited six stores in Wakefield, six in Castleford and two in South Kirby as part of an ongoing programme to tackle knife crime.
The pair were sold a large kitchen knife by a member of staff at one Wakefield store, who was informed he had failed a police test purchase shortly afterwards.
The man was given a community resolution and advised his store would be monitored.
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Legally, knives with non-folding blades over three inches long should not be sold to anyone under the age of 18.
Inspector Helen Brear, of Wakefield District Police, said: “It is positive news that of the 14 retailers visited by our test purchasers, all but one were vigilant and refused the sale of knives to the young people.
“It is disappointing that one Wakefield retailer sold a knife to our test purchasers however, and we have now issued a community resolution to the staff member responsible.
“We will be monitoring the store in question and will be carrying out more test purchases in the coming weeks and months.
“The law on the sale of knives is very clear and it is important everyone plays their part in keeping these items out of the hands of young people.”