Amber Rudd is shown a collection of knives by Superintendent Sean Yates that have been involved in knife crime in London at Southwark police station yesterday

People buying knives online will be forced to collect them in person under a government proposal to clamp down on sales to children and teenagers.

Online age verification checks have failed to stop under-18s obtaining knives, the home secretary admitted.

The Home Office proposal means that instead of having a knife delivered to their own address, buyers would have to arrange to pick them up from a store, which would be responsible for checking their age.

How online sellers without physical stores would comply with the legislation will be considered as part of a consultation this autumn.

Amber Rudd, the home secretary, said: “We are announcing new measures to combat knife crime and the devastating impact it has on families, individuals and communities.

“We are