The fire alarm was activated and the Underground station evacuated at the Bridge about an hour ago and it reopened about 18.10-Ish. As far as I'm aware it only affected the Underground station.
According to the station staff at Blackfriars NR and St James's Park tube, plus automated announcements, the evacuations at both stations were for security reasons. London Bridge (hereafter referred to as LBG; VIC is London Victoria and BFR is Blackfriars) seemingly had its tube station and (briefly) its NR station evacuated.
I was very much caught up in this. I feel I should post my tales of this evening's woes! It's a long post...
When I left Goodge Street tube station sometime between 1745hrs and 1750hrs, the dispatcher was announcing that "London Bridge station is closed and passengers are strongly advised to use alternative stations". There were no further announcements onboard my Northern Line train; there may have been announcements at Embankment, where I changed trains, but I did not hear any; there were none on my District Line train to Victoria.
On exiting Victoria in what began as a normal manner sometime around or before 1810hrs, it quickly became apparent that there was severe overcrowding on the stairs to the NR concourse from the Victoria Line ticket hall. I surmised that the emergency crowd control barriers must have been closed, and I was just about able to see that I must have been correct (I later saw that this was the case from across the road by the bus station). I was unable to proceed to any part of the NR concourse to catch the 1819 VIC>HRH. Crowd control was absolutely terrible and totally disorganised; there were no station or staff announcements until crush conditions in some of the Victoria Line ticket hall occurred. There were absolutely no staff attempting to direct passengers out of alternative exits and no staff were in the station control room by the Victoria Line barriers; passengers were still being sold tickets. At approximately 1817hrs, there was one announcement that passengers requiring VIC NR should be careful of the crowds and that they should consider leaving by an alternative route "as the stairs are now closed to Victoria National Rail station".
There were then a series of muffled announcements that I could only describe as unclear and potentially frightening for passengers about how the District and Circle Line platforms should be evacuated by staff due to "an incident". This was at about 1820hrs. To give you perspective, I was struggling to find a way out that was not packed-out at this point, and was still near the Victoria Line ticket barriers. Shortly after this, there was an announcement that the Southbound Victoria Line platform should be evacuated by platform staff. No formal evacuation alert system seemed to be in operation. The ticket barrier staff did not close the gateline and people were still boarding escalators to the Victoria Line. I did not hear a single evacuation message for the whole station, nor for the Northbound Victoria Line platform (if a staggered evacuation was deemed necessary, this I can understand), although most passengers were, by then, realising something was seriously wrong, and making their way up the very congested stairs near the District and Circle Line gatelines.
I then walked through the many crowds of people outside the entrances to the District and Circle Line concourse, where there were no staff whatsoever and where people were being allowed to wander in, although most were not and the pavement was pretty congested. I helped a few passengers exiting with me to find St James's Park tube station, to which I also went. (Any terrorist would surely have had terrible but "effective" results if they had chosen to detonate a real device amongst or start shooting at any of these crowds I have just mentioned.) At this point I had no idea if there was a wider security alert, nor did I know if the closure of London Bridge was still ongoing. A very polite member of staff at St James's Park advised me not to go to LBG as, and I quote, "I don't know what's going on - something
is going on - nor do I know exactly whether or not it's closed", and said that VIC would be closed for "a while". I took a District Line train to BFR, where I made my way to the mainline platforms. I spent a while waiting and discussing the issue with the polite and considerate, but unfortunately very-ill-informed, gateline staff on NR Platform 1. They told me that LBG NR was "sort of" now open after "an earlier evacuation". They thought it was a security alert, and the automatic announcements said so. FCC had some delays stacking up, but I managed to catch the delayed 1905 to Brighton, which arrived with moderate delays at East Croydon, after becoming properly rammed at LBG! I found the total lack of driver announcements on this service
very disappointing.
From there I caught a train to my destination (this was a service from VIC, with delays of surprisingly just a handful of minutes, to stations which I won't specify), arriving with around an hour's worth of total delays. Other trains at ECR had delays and alterations of a far greater magnitude - most prominently delayed were the FCC services!
I should add that the above account is from my perspective as (in this case) a passenger; none of the details are fictional or exaggerated.