Manchester Arena plotter’s alleged prison attack sparks call for US-style rewards system

The report is understood to recommend that for the most dangerous prisoners privileges can be earned or taken away depending on closely monitored standards of behaviour. Photograph: Paul Faith/PA

A long-awaited report that examined how the Manchester Arena plotter was able to carry out an alleged violent attack on prison officers has recommended a new punishment and rewards system for the most dangerous inmates, similar to that used in a US Supermax jail.

David Lammy, the deputy prime minister, is facing demands to publish the report, which looks into why Hashem Abedi, who was jailed for life for helping his brother carry out the 2017 bombing, was able to target staff at HMP Frankland with boiling oil and homemade weapons in a planned ambush.