Since RSI has formed part of the discussion today I thought I'd post a chart showing those details (thanks to Gary for pointing out the RSI breakout backtest).
The lowest RSI support goes all the way back to June 2007 where it was at its lowest value. Since then the 4.5p low formed a higher high and a bullish divergence. This same RSI support has come into play only twice since: once at the 87p low and just recently at the 126p low.
The top RSI resistance comes from the bearish divergence from when the price made a peak of 320p and then the 450p high. Since then it was hit on the rise to 228p showing that that level was a good place to sell/short. There is another RSI resistance above this which comes from the 2009 131p high and the 450p peak but it's off the top of the chart.
Finally we have the RSI breakout from the downtrend from the 228p price level. This occurred the day before price made it's big move up from 129p again, signalling a move. We're now back at that short term RSI as Gary mentioned so it'll be interesting to see if it bounces from here