The government is increasing the number of police officers trained to deal with chemical, biological or radiation "dirty bombs", the BBC has
learned.

Source
To me it looks like a hint of another planned attack on England. This quote here, I feel, backs me up
The Association of Chief Police Officers (Acpo) said the purchase of the suits was "part of a sensible, planned investment programme".

They may be trying to ease fears about a dirty bomb, but this is fuelling speculation.
The link below shows what could happen if a dirty bomb exploded in London
Dirty bomb in London scenario