Officers teamed up with police cadets to carry out a test purchasing operation in shops across Burnley after an increase in children smoking vapes.
A spokesman for Burnley and Padiham Police said: "This weekend we have been test purchasing with the cadets after we have seen an increase in children smoking vapes. Many parents have been contacting us to pass on information about where children are managing to buy them.
"We have test purchased at numerous premises and all but one shop challenged the young people asking for identification and refusing to sell to them. The one shop that failed has been spoken to and will be reported to licensing for further action."