In the years before the student protests, it had become common practice to charge protesters with violent disorder under Section 2 of the Public Order Act 1986, the second most serious offence after riot, which carries a five-year maximum sentence. Despite the range of options and charges open to the police and the CPS, they had more recently resorted to using Section 2, treating protesters as if they were football hooligans. Keir Starmer QC was the director of public prosecutions during that period.
Excerpted from "Charged" by Matt Foot (a history of how the police, parliament and the judiciary have attacked protest and slowly eroded the right to do so, well worth a read). Starmer crops up a lot, initially as a "human-rights lawyer" and then "surprisingly" he jumps to the other side becoming the DPP.