Oldest vehicles in regular service/use?

[Wumpty]

What are the oldest buses in regular service/use you know of? These can be service, private hire or ancillary work where they perform a critical function.

Former NXWM Timesaver Metrobus DP D957NDA has been in regular use at Wolverhampton as their Bistro Bus for drivers to take rest breaks on, and forms part of the heritage fleet available for private hire work.

Any others?

[Stu]

What are the oldest buses in regular service/use you know of? These can be service, private hire or ancillary work where they perform a critical function.

Former NXWM Timesaver Metrobus DP D957NDA has been in regular use at Wolverhampton as their Bistro Bus for drivers to take rest breaks on, and forms part of the heritage fleet available for private hire work.

Any others?

If you're counting private hire work, how about this one?
http://wmbusphotos.com/NXWM/3225-3614/3225.html

[Wumpty]

If you're counting private hire work, how about this one?
http://wmbusphotos.com/NXWM/3225-3614/3225.html

I was so fixated on the heritage fleet currently under restoration, I clean forgot about the oldest member of the fleet :o

Top shout @Stu

[DJ]

Go North East used their 1964 Routemaster in service last year, to provide extra capacity at peak times.

https://www.gonortheast.co.uk/extra-buses-including-classic-1964-northern-general-routemaster-deployed-keep-people-moving-schools

[Ian Hardy]

On London Underground strike days Ensignbus and the London Bus Company regularily use their RTs on extra journeys on route that parallel Underground lines. Most date from 1950 but Ensignbus also use RT8 dating from 1940. Next week it looks like they will be running again as the RMT are going out on strike:
https://tfl-newsroom.prgloo.com/news/tfl-press-release-tfl-warns-customers-of-potential-disruption-due-to-planned-rmt-strike

[Wumpty]

Midland Classic of Burton on Trent operate prototype Metrobus TOJ592S regularly on their services.