Any careful plan will have another "standby" train for use , after the last advertised one in an event like this.
They did. (GTR are well versed in this sort of stuff. They used to do it with unadvertised stoppers which always ran down the BML after the last advertised trains on Christmas Eve as well, though it’s since proved a sheer waste of resources.)
I am not sure it did.
Much of what he proposed has been done - using GTR to service the overnight railway rather than Southern at Victoria. He argued probably correctly that the overnight railway was over supplied and was a legacy of the competition between 3 separate franchises that became enshrined in franchise agreements instead of being rationalised. There railway isn't very good at rationalising it's timetable.
He also suggested the Redhill loop not be served Sun-Thur in the small hours to allow overnight trains to alternate between routes at will. But a comprehensive overnight timetable was produced in Appendix 3.
There is massive demand from Gatwick into London even past midnight and scheduled landings most of the night. The timing of demand is also determined by flight delays and passport queues. Final takeoff is about 11.30 but Gibb only graphed outbound passenger numbers for some reason.
To counter those points, Gibb missed out several things (as ever in his report, and indeed doubtless in his scrutiny of the May timetable change, which was dealt with by the Transport Select Committee).
The overnight railway in the Sussex was remarkably flexible, especially before drivers’ diversionary route knowledge around South London was somewhat removed. The Southern service was usually busy, and most of the same route is served now, without significant disruption, when overnight Thameslink services actually run, subject to driver cover. Although it is fair to say that there is more overnight single line working nowadays around the Purley to Gatwick stretch, a properly planned service could still maintain a Southern option, which used to cater neatly to a lot of overnight tourist, entertainment and employment options around the West End, something which Blackfriars is mostly inconvenient for, likewise other TL Core stations.
Rationalisation had already happened - many GX services have been eroded long before the Gibb report arrived - the Southern options served everyone quite well, as they ran like clockwork, weren’t usually especially slow, and mostly had capacity to spare for airport passengers, except around party season near Christmas. TL was always the unreliable cousin and nobody much relied on them to get to the airport, although they had some local traffic. It’s much the same with TL now, except there’s often no reasonable Southern alternative. I can personally vouch for seeing long streams of cars on the A23 et al between London, Croydon, Gatwick and Crawley, late into the night heading both ways, and early in the morning heading to the airport. The road traffic seems to have increased exponentially in the last year, certainly the last few months.
Skipping of the Redhill “loop” (actually a mainline in its own right) is sheer folly. Redhill has almost no overnight public transport and there is surpressed demand which has often been clearly seen. I used to regularly commute on the 0102 Victoria-Brighton; always a busy train and most passengers used to pester anyone in a railway uniform to see if it would do the staff stop at Redhill (for which all doors would regularly be opened, and anyone could board or alight). It mostly did stop, and half the train would alight. There are so few options from useful parts of London that people are deserting it as a “railhead” type of station, but it never had to be abandoned in that way, especially as the infrastructure on the Redhill route is actually considerably less troublesome than the Quarry Lines, and much of the track patrolling via Redhill can still be permitted between trains, unlike the Quarry.
There’s also been a fair bit of deception as the reduction of the overnight service was, of course, promised to be temporary. A big “hmmm”!
....and, hopefully, another 2 or 3 'just in case'.
That was done as well.
I travelled from London last year for a concert that would have finished at about the same time (significantly smaller than Britney, it was at West Hill Hall) and although crowded, it wasn't a shambles like this appears to have been. The queuing was well organised, and even coped with a full train being cancelled about 20 minutes after its scheduled departure time as they couldn't find anyone to drive it. I got on the next train without a huge problem, and it was standing room only but certainly not dangerously full.
London has many mainline termini and interchanges (one reason why termini can be superior to through running) to which people readily disperse. In extreme situations they can act as compass-point queuing points and can absorb an awful lot of people that way - but a single concert would probably never lead to this at more than one or two stations.
The capacity of a 12 car class 700 is 1088 (including standees). That's 53 trains before one even considers Brighton Pride. Add to that the fact that a class 377 of the same length can take fewer standees.
You can fit a hell of a lot more people than that in a 700. 1300 could be accommodated without too much fuss, more if crush-loaded. The fact is that some trains were leaving Brighton empty anyway, so this was not the most pressing problem. The ebb and flow of people into the station was not well-controlled (by some accounts, the BTP lost control, which isn’t surprising as they are chronically under-resourced in the Sussex area in particular).
And that’s not accounting for the fact that by no means all the people attending this event would use the trains, so you’re not transporting everyone.