A 15-year-old police cadet caught out two Eltham shops after the retailers sold the undercover teen blades and knives.

The test purchase was part of Operation Sceptre, a London-wide Met Police campaign to tackle knife crime.

The police cadet successfully bought a craft knives from one another independent retailer and razor blades from another without being challenged for proof of age.

One of them has been subject to a formal caution and the other is now facing further investigation.

Under the Criminal Justice Act 1998 which prohibits the sale of such items to under 18s.

Jackie Smith, cabinet member for community safety and environment, said: “Cracking down on underage sales of such potential weapons is a key part of our anti-knife crime strategy.

There will be serious repercussions if you are caught selling such dangerous items to young people and we will not shy away from taking robust enforcement action where we can.”

Borough Commander Simon Dobinson said: “This is another successful example of close partnership working with the Royal Borough of Greenwich to stop the sale and proliferation of potentially very harmful weapons to young people.

“We will continue to take the firmest action possible to eradicate knife crime in the borough for good.”