9Pence

The problem is not solely one of water. The historic barrier to tunnelling in south London is one of the composition of the London sub soil strata, in so much as variability of it's makeup. Have a look at the attached diagram. The picture shows us ground water levels 'the water table' is without doubt rising evenly and right across the entire London basin. This is a process that has been going on for a considerable number of years. Water of itself is not an insurmountable problem to tunnelers. After all there are plenty of traffic communication tunnels under water with plenty more planned. There is a large red vertical arrow pointing to a fault line just south of Lambeth marked 1. A little further to the south there is another line (not arrowed) marked 2. It is these fault lines which are the problem with tunnelling in south London. At these points the sub soil at a fixed depth radically changes in composition. The change in water level from water impermeable London clay to permeable Lambeth Group is also an issue. Lambeth Group is a strata permeable to water. It is composed of silts, gravels and medium sized post glacial erratics. The problem of the high water level can be overcome but what cannot be so easily be overcome is the combined effect of high water AND unstable subsoil. It is tunnelling through the sub soil boundaries between the two strata that is the tricky bit. It is dangerous, challenging and ultimately a very very expensive transport solution for south London. These boundaries, marked here as vertical lines, do not just exist in just one dimension. They stretch right across south London to the east to Kent and in the west as far as Windsor then beyond. Anyone remembering the tunnel work undertaken in south London for the extension of the Jubilee Line will recall just how much these south London gravel beds were the source of numerous delays and very expensive postponements to the original opening schedule. Boris Johnson now tells us tunnelling technology has moved on in the past 25 years. Indeed it has. It has now reached the stage where extensions to the London tube network via tunnels mean it is possible to tunnel safely and economically through regions which to earlier generations were impassable. In 1903 it was decided to terminate the Bakerloo Line at Elephant and Castle. Elephant and Castle station is placed precisely on this Lambeth boundary, between the two soil strata. Termination was necessary as they did not have the where with all to safely extend the original line on and into the Old Kent Road.

Yeah here's a TfL type of map. Only thing is the map really does show the new line completely and totally avoiding the Camberwell option(s). The Bakerloo extension is so desperately needed it's no longer a political gambit. For commuting Londoners in the south east it's an essential as good schools for children or decent healthcare for the elderly. Population density and room for growth determine how these things impact in our daily lives. Transport more so. Boris wants to put south east London on the tube map and he wants to invest both his and the Gvmt's money wisely. The professed logic for money for public transport infrastructure is people numbers - population density to you and I. It doesn't much matter what they're doing. They could be shopping, working or at leisure - makes no difference at all just so long as they're moving from A to B or from B to C or C to D. It's all about movement figures, 'cause movement figures indicate growth. Take any town, village or city in the UK, the same rules apply. It is the projected number of passengers per hour the train, the bus, or the tube will carry that determines much if not all of todays transport policy decisions. Ironically in London to build public transport infrastructure you must first find the empty places. It is where people don't currently live new transport can make the biggest difference. For biggest difference read make the most healthy returns on investment. People need space to grow so it is in the empty wards with space available where new transport makes the most difference. The same logic says if all the land is developed you cannot enhance or uplift transport revenue with new investment. In the latter case revenue could only be generated by changing people's established work, leisure, travel pattern. That's nothing like as profitable as finding an empty space, developing it with high density housing and then offering those same people the opportunity to travel to their place of work/leisure or shop in super fast, spanking new trains. Much Much more profitable. Posted at the bottom is one image of three maps. They show local Geography (Google), Infrastructure (TfL) and Population Density (HMG). The last map shows the empty space in south east London. The more faint the blue the more space is available for growth. The more dense the blue the less opportunity there is for high growth. This map also shows one continuous corridor of 10 white zones. These stretch from Lewisham in the north to Hayes in the south. This is the South East London Development Corridor. One large contiguous region representing huge opportunities for growth and investment. Geography shows us the way the human landscape evolved. The historic reasons why people in south east London live where they do. Rivers, streams, hills, canals and even the local weather have all played their part in shaping our collective human geography. Infrastructure shows us where Boris, TfL and Lewisham Council would like to put their new Bakerloo tube line and stations. Population density shows us why TfL, Boris, Lewisham Council, the GVMT and The Treasury want to put the tubes lines there in the first place. The population map is from 2011 (so it's up to date) shows the eight zones(1-8) for population growth, IE space in south east London. The eight zones with the highest available space are all to be linked and/or traversed by the new Bakerloo Line extension. Could be coincidence but somehow I doubt the boffins at The Treasury and County Hall missed this little trick. It's more likely to be a case of intelligent people doing the most obvious thing with their money as opposed to investors doing the strangest thing. Not a bad way to go if you want to put as many people as possible, on the tube, on one line, in one huge scheme and all in one go. The current Tfl transport plan only omits two zones out of the original ten under populated zones previously unconnected to a major transport hub. In this case Lewisham. Eight out of ten and it's suddenly apparent the job of putting south east London on a tube map near you is no longer all talk. It's all done. If there's space then there's growth. If there's growth there's money to be made. At the end of the day transport for south east London is not about trains, carriages, sidings or tunnels, embankments, points and signals. It's just all about money, money and space. Simple as that.

'The various possible routes were reviewed in 2012 and the benefit:cost ratio favoured one via the Old Kent Road rather than into Camberwell and Peckham.' Now let's all guess which one they'll go with. This is not rocket science. My ?50k says Camberwell won't be getting a tube station. Not now. Not never. Not ever. Sorry Camberwell.