Knife crime involving under 18’s and adults from January 2015 to May 2025
Freedom of information request reference no: 01.FOI.25.046488
I note you seek access to the following information:
We have recently been supplied with this FOI data by the Met (see excel sheet).
The data seems to suggest a massive decrease in knife crime offences covered by the FOI request.
However, we have since been advised by the Mayor of London’s office that the Met has, as of recently, changed its recording practices. This means that 2024/2025 data is not comparable with previous years.
Can you please confirm why it is this change has been made and what changes have been made to the way knife crime offences are recorded, particularly those involving people aged 18 and under.
Please also confirm which of the categories you have sent me data for have changed, as we will need this to be able to accurately report on the matter.
Can you please provide me with any other alternative data to give us an accurate picture of the state of knife crime and young people aged 18 and under in London.
Decision
I have today decided to disclose the located information to you in full. Please find below information pursuant to your request above.
Background to your request:
You have said:
We have recently been supplied with this FOI data by the Met (see excel sheet).
The data seems to suggest a massive decrease in knife crime offences covered by the FOI request.
I have made enquiries with the Data Analysts who dealt with your previous Freedom of Information Act (FOIA) request, and they have advised that having reviewed your request, it has come to light that there was an error in the data provided to you for FOIA request 01/FOI/045172. Specifically, the age ranges used in the searches were incorrect. I apologise on behalf of the MPS for this error any for any inconvenience caused.
You have commented:
However, we have since been advised by the Mayor of London’s office that the Met has, as of recently, changed its recording practices. This means that 2024/2025 data is not comparable with previous years.
Can you please confirm why it is this change has been made and what changes have been made to the way knife crime offences are recorded, particularly those involving people aged 18 and under.
Our Data Analysts have advised that the MPS implemented a new crime recording information system called Connect, on 27 February 2024. This new system replaced the CRIS database that had been implemented in 1996.
Connect utilises a fundamentally different database design which means that some data is recorded more accurately than it was previously. The way in which markers are applied to records is one such element.
On CRIS, a knife crime marker was added to a whole crime record. This meant that all offences recorded for a given incident were counted as knife crime. On Connect, markers can be added to specific crimes rather than all crimes in each investigation. The same applies to domestic abuse recording, hate crime and even how we count victims relative to offences. It is this change to a new recording system which makes datasets pre and post 27th February 2024, incomparable.
You have said:
Please also confirm which of the categories you have sent me data for have changed, as we will need this to be able to accurately report on the matter.
Please find below a revised dataset for FOIA request 01/FOI/045172. Kindly ensure that the data is read in conjunction with the notes page of the spreadsheet. Additionally, as advised previously, as age is not a mandatory field within the CONNECT system there are likely data inaccuracies within some of these results to be considered. Additionally, as advised before, knife crime accuracy figures are not always on target and this needs to be taken into account with some of the finer numbers.
You may wish to consider contacting NHS England for data on hospital admissions for assault by sharp objects. The link below to some of their published data may be of use to you:
NHS | Hospital admissions for assault by sharp objects - February 2024