Shady security privateers Serco and G4S took a hammering yesterday after a review into their combined £5.9 billion worth of government contracts unearthed shocking behaviour by the two firms.

Serco has agreed to repay the government £68.5 million for overcharging on tagging contracts - including for offenders who were back in prison, overseas or dead.

G4S has not agreed to give any money back, but discussions continue.