Your report (I was a victim of scooter phone thieves, says home secretary, 18 June) highlights the lower “sanction detection” rates in the Metropolitan police for burglary (5.5%) and robbery (7%) than for offences generally of 13.2% in 2017-18. The term refers to offences where those responsible were not only identified but were subject to some formal penalty. It has always varied by offence type.

Far more important is the fall in the overall sanction detection rate. This has always been lower than the national average in the Met, but appears to have fallen by 40% in just five years. In 2012-13 the Met’s overall sanction detection rate was 22%, against an average of 27% across all forces in England and Wales (with figures for burglary and robbery of 12% and 21%).

The Home Office no longer gives figures for detections of any sort, let alone sanction detections. As it explains, from April 2013 detections were replaced by a new “outcomes framework”. This now requires forces to assign one of 19 specified outcomes to every crime they record.

The failure of the media to spot this seemingly unprecedented fall in the detection of crime may in part be explained by the confusion created by this substitution.

However, one eagle-eyed journalist focused simply on comparing the first of the new “outcomes” with the comparable type of sanction detection; and it is difficult to understand the lack of coverage for his key finding. For, as the Panorama programme Police Under Pressure (BBC One, 16 May) reported, while recorded crime increased by 21% in the five years to the end of March 2017, the number of offences that resulted in a charge by the police fell by 10%.

Marian FitzGerald

Visiting professor of criminology, University of Kent

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