Customers and staff feared for their lives when an explosion ripped through the Lady Margaret pub in Southall last week.
The explosion, which happened just outside the pub late last Thursday evening (October 18), caused windows to smash and resulted in damage to the inside of the pub and the front door.
Police investigating the nail bomb attack at the West London pub said luckily there were only about 20 people in the pub at the time and nobody was injured.
They said they did not believe it was a terrorist attack.
"There is no suggestion that this serious incident is linked to the atrocities in the US, the subsequent military action in the Middle East or to Irish dissident republican groups," a Scotland Yard spokesperson said.
Pub assistant manager Sue Day told reporters: "It was very frightening. We were getting ready for closing and suddenly there was this loud bang.
"The windows went in the doorway and the pub filled with smoke. I have no idea why someone put the bomb there but it is a miracle no one was hurt."
Ms Day added: "The door is very badly damaged and all the windows in the doorway are shattered. It's a mess."
Police are treating the incident as a local criminal matter and think it could be linked to an earlier shooting in Cranleigh Gardens, Southall, just 200 yards away.
They are appealing for anyone with any information to contact them on 0800 789 321.