Mark Leftly: Two giants let us down, but at least they have now made the necessary sacrifices

Serco's parallels with G4S grow more astonishing by the day, even allowing for the fact that both have been implicated in the electronic tagging scandal.

They are entrusted with running and protecting vast swathes of our public services, and have let the country down.

G4S is most infamously known for failing to provide 10,400 guards for the London Olympics, a source of national pride but a contract that was small fry for a group that employs 620,000 people. Serco is a similarly sprawling group, involved in everything from schools inspections to training military helicopter pilots.

Both groups are too vast – empires rather than companies. They are unwieldy and cannot be controlled, so senior directors are unable to properly keep track of managers running operations on the ground.

That means they make huge mistakes. Let's be clear, G4S being synonymous with the Olympic failure and Serco with the electronic tagging and prison van scandals blurs many far greater errors.

For example, Serco was fined a mere £200,000 earlier this year for an explosion at, of all places, the Atomic Weapons Establishment while G4S "secured" the US nuclear facility that was infiltrated last year by a group of protesters led by an 82-year-old nun.

Nick Buckles, the long-time G4S chief executive, resigned far too late when he finally admitted defeat in May while Mr Hyman should have gone in the summer. Neither knew how to react to their respective scandals, so unused as they were to being subjected to public scrutiny – despite taking our money.

Worst of all, both are companies too important to fail. They are now as fundamental to the public sector as any Government department: getting rid of them from public life is unfeasible.

All the Government needed to keep using them were these sacrifices, no matter how belated.