I think people are being unfairly harsh on the member of the public that reported this. For anyone who uses the Tube in London, you'll see posters everywhere asking you to report anything suspicious. For all this guy knew, something suspicious and untoward was going on which could have endangered the lives of the people on the bus.
I'm sure they didn't ask for the armed police etc to be sent, it was merely escalation based upon what was reported to them.
Let's also not forget that the current threat level in the UK is at "substantial" (http://www.homeoffice.gov.uk/counter-terrorism/current-threat-level/). Things like this are taken very seriously with a heavy handed approach for good reason. If another 7/7 attack happened then both the police and secret services would be criticised massively.
I'm sure they didn't ask for the armed police etc to be sent, it was merely escalation based upon what was reported to them.
Let's also not forget that the current threat level in the UK is at "substantial" (http://www.homeoffice.gov.uk/counter-terrorism/current-threat-level/). Things like this are taken very seriously with a heavy handed approach for good reason. If another 7/7 attack happened then both the police and secret services would be criticised massively.