We published this letter retrospectively on 28 February 2024, as it was referred to in a Freedom of Information request.

Dear Vivienne

Mayor’s Office Violent Crime Statement

We wished to follow up on the recent case regarding the use of crime statistics by the Mayor’s office. This related to a statement by the Mayor of London on violent crime on 20 July 2023.

We have engaged with the Mayor’s Office for Policing and Crime (MOPAC) and they have been open and helpful in providing the source for these claims.

Having reviewed the source, we have found that part of the statement is incorrect and has the potential to mislead the public. The original analysis looked at the change in knife crime with injury (under 25 years) which has decreased across the relevant period. However, in the statement, the Mayor’s office references knife crime as a general category which has significantly increased across the relevant period.

It is important that such statements accurately reflect the evidence – particularly on topics of high public interest. One way of supporting this is to encourage communications teams to work more closely with analysts when preparing these statements. We would be grateful if you could engage with the team at the Mayor’s office to ensure the statement is corrected and to support them in reviewing their processes for using such analysis when informing their outputs.

Yours sincerely

Ed Humpherson