There are lots and lots of stories about HS2, but this Q&A from the BBC is cracking. It summarises the pressure groups involved, the government involvement and much more. The StopHS2 campaign are a good example, and an up to date example, of a pressure group following quite traditional actions. This is particularly notable as it cannot be said that they are in insider, being directly opposed to the government, and therefore they are a good example of an outsider acting within the law, which so many do not.
It is also a useful example as the Treasury Select Committee have been investigating HS2 and taking expert opinions (http://www.theguardian.com/uk-news/2013/nov/05/hs2-report-overstated-benefits-expert). HS2 therefore provides you with an example of the workings of Committees in Parliament which forms a section of Unit 2