Although the network wasn't privatised in 1991 its effects were already been felt. Yes the 153 was to replace 1st get, but BR already knew privatisation was going to happen and savings were been made as a result. For example May 1992 was the year many regional railway services were cut to make the lines more attractive for privatisation as they were going through writing the specification. When the 153 replaced the 156 on my local route (Newark - Cleethorpes) BR had to raise prices, make connections worse etc to reduce the overcrowding. Any services after 2000 were killed off in Lincolnshire,
The '92 election victory for the Tories was the one the pundits all got wrong. By most people's reckoning Neil Kinnock should have been in No. 10 when it happened. John Major pulled off a significant comeback, and whilst he had a very small majority the Conservatives actually polled more votes than they ever did in an election under Margaret Thatcher.
Prior to privatisation BR had in many areas become vertically integrated, with the sectors responsisble for their infrastructure. As such the sectors had to watch all their costs. It's one of the reasons the 153s appealed for Regional Railways, as it gave them a fleet of single car units to use on the rural routes.
As to stock in development, well the Class 93 and
Mark 5 coaching stock (IC250) would have been built for the West Coast.
The Mark 3 loco-hauled fleet would have been cascaded, probably to CrossCountry (though maybe Anglia too). InterCity had already started prototype development on the next Mark 3 refurbishment, showing the Mark3 still had a future with InterCity.
NSE was looking at the
Clubman for longer distance services out of Marylebone - was it to be Class 167, given that the eventual Clubman took the 168 number?
Also as has been said the Networked family was to be NSE's EMU family of choice. After the 465/466 fleet was to be the
Class 471 to replace the Kent Coast slam door stock.
Crossrail was to have the
Class 341 and Thameslink the
Class 371 (after the Thameslink 2000 upgrade).
For Regional Railways the only new design on the horizon was the Class 157, to be built by Hunslet for use on Strathclyde PTE services.
West Yorkshire PTE electric services could also have been handled by a further build of Class 323 units. As it was the Class 308 units had to soldier on until the Class 333 units were eventually ordered.