Police patrols across the West country were stepped up on Thursday to reassure people in the wake of a series of bombings in central London.
All train services to London from the West were cancelled
Avon and Somerset Police brought in a number of high-visibility patrols in the region's town centres.
More armed officers were also on duty at Bristol International Airport.
Assistant Chief Constable Rod Hansen said: "We have no information to suggest our area is under threat, but this is an obvious precaution to take."
Other emergency services across the area were on standby to help in London and elsewhere.
Bristol Royal Infirmary and Bristol Children's Hospital were on alert to receive casualties if necessary.
Gloucestershire charity Rapid UK, which provides search and rescue volunteers in disaster zones around the world, was also preparing to go to London if called on.
The Bristol-based National Blood Service said their current stocks were healthy, but they have urged anyone who has a donation appointment in the coming days to make sure they attend as planned.
And the travel chaos in London had knock-on effects across the West.
The bomb disposal team was called in at Swindon railway station
First Great Western's services into London were affected and all buses from Bristol to London, including National Express, Megabus and Bakers Dolphin services, were initially cancelled.
Megabus was expecting to resume services during the early evening.
There was a security alert in Swindon shortly after details of the London explosions emerged, when a suspicious package was spotted at the town's station.
The area was evacuated and bomb disposal experts carried out a controlled explosion, but the parcel was found to contain two gifts and a bag of washing.
Rail managers asked people to be flexible with regards to travel on Friday.