Today the zone 1 boundary moved south to Kennington station and then along the Northern line to Elephant & Castle. This means that Kennington is now on the boundary between zones 1 and 2 rather than in zone 2 alone. The reason for this is because the new Northern line extension to Nine Elms and Battersea Power Station will be in zone 1 as part of the agreement with the owners of the new development. They have been promised zone 1 status so that fares to the rest of Central London are not inflated by an extra zone.
This is all very well, but what about Vauxhall? As you can see on the map, Vauxhall is very definitely north of the new extension. Like Kennington and Elephant & Castle it is currently in zones 1/2, meaning that passengers travelling from the south do not incur a zone 1 fare. Now I readily admit that you can’t get from Vauxhall to either of the new stations directly, so there isn’t a technical problem in the same way that there was at Kennington. But just how are they going to show the zones on the map?
The diagramatic tube and rail maps could push the extension above Vauxhall. It wouldn’t be the first time something like this had happened (just look at Bethnal Green), but I can’t help thinking it would be confusing if they do. A more radical approach would be to put both new stations in a zone 1/2 sausage (like Stratford to Canning Town) but they’d then have to charge zone 2 fares between Battersea and Elephant & Castle.