Stricter measures will be introduced in Liverpool, Warrington, Hartlepool and Middlesbrough
The BBC understands a three-tier system will aim to replace the current patchwork of local lockdowns.
Stanley Johnson has apologised - as has former Labour leader Jeremy Corbyn, who broke the "rule of six".
Duke and duchess say there have been changes but "sufficient progress" has not been made.
The incident is the third shooting to happen in the Black Country in the past three days.