The Military will now take over from Police Officers at protected sites as officers are released to carry out armed response duties.
The Prime Minister Theresa May has now raised the threat level to the highest possible rating meaning another terror attack is expected imminently.
Terror Cops have launched a manhunt after an Improvised Explosive Device (IED) caused a fireball to rip through a packed London Underground train carriage in south-west London.
The military has now been called in to replace police officers as guards at protected sites which are not accessible to the public.
More armed police will be deployed on the public transport network and on the streets ensuring extra protection is in place.
Theresa May said “This is a proportionate and sensible step which will provide extra reassurance and protection while the investigation progresses.”