I've not commented much recently on the ongoing plans by the developers of Battersea Power Station to extend the tube from Kennington to a new stop named Nine Elms and through to Battersea itself although I remarked on the initial consultation.
There was a post back in July highlighting the fact that there would be tunnelling under South Lambeth from over at the Albert Square and St Stephen's Association blog. They've also pasted a very helpful tube map of what the extension would look like if it were built.
However, various blogs have been picking up the matter, and things have hotted up because the developers of the power station have submitted informal plans for the Battersea site itself. It's worth noting that that means nothing as yet since transport has not been mentioned in their plans. There have also been plenty of plans submitted by various developers that have had to be abandoned. Yet, some of the people over at London Connections became excited in July when it appeared that feasability studies had been completed and various parties were happy with the route. They even mention the fact that London Underground are looking into funding the line to continue on to Clapham Junction, so the northern line would head off West eg. Kennington > Nine Elms > Battersea > Clapham Junction. Boris Johnson is also understood to be supportive, and methods for raising funds by selling government bonds have been suggested.
So, what makes me raise the issue? I received a query by email about a week ago from somebody who said:
"I've just been talking to my local councillor and he says that there are plans to extend the Waterloo and City line through the Black Prince Road area to Vauxhall and Battersea as part of redeveloping Battersea Power Station... But he says that the developer wants to use the Northern line instead so that they don't have to go through working class areas, cos they only want rich guys turning up at their buildings. Is this true?"
I've no idea which councillor the article refers to, but this tale sounds like the conflation of several ideas. As far as I can tell, there has never been a plan to extend the Waterloo and City line (although this would be preferable as it would mean that the northern line and the Bakerloo line could be taken into the areas of South East London that are much more in need of the transport eg. Peckham, Lewisham). It strikes me as highly unlikely that the Black Prince Road area would be included, simply due to the money that it takes to build the stops. The Nine Elms stop, one presumes, is being built entirely for the US Embassy at Nine Elms and (hopefully) they'll be asked to fork out the cash. The Battersea stop would be included in the costs for the new development at Batterse. However, if you take a look at the London Connections comment section on the above article, you'll see that there's a fair amount of discussion about alternative routes, and there are various suggestions that it would be better to use the Waterloo and City line... Unfortunately, I've not heard any official discourse on the matter at all so we'll presume that if it goes ahead, it will fork from the Northern line and some of us are rather sceptical that the plan will go anywhere...