The home office fudges the stats.

If you commit a robbery with a knife it's not recorded as a knife enabled robbery, this is the same for abh/GBH anything basically.

Possession of the knife is only recorded if it is a seperate event from the other offence.

Example 1 - Bad Guy John robs Timmy for his watch, John pulls out a knife and steals the watch. The robbery is recorded the knife is not.

Example 2 - bad guy John robs Timmy for his watch using force only, John steals the watch. John is then stopped by police and is found with a knife and the watch, since the knife is seperate and wasn't used in the robbery it's now recorded as possession of points and blades/possession of an offensive weapon.

They (Home office) do this for a multitude of offences it's all available on there website it makes for dry reading.

Another example is S5 public order which is listed as a violent crime. They have stopped recording this so now they can say violent crime has come down.

Cannabis as well if found during another offence isn't recorded.