In 1997, Jack Straw arrived at the Home Office with a stark agenda. The police were in dire need of "modernisation", along with those other behemoths of the public sector, health and education, and this could only be achieved by "new thinking". The key driver for police reform was, and remains, the exorbitant cost of paying and equipping police officers. Linked to this was the pensions "timebomb". The Home Office recognised that something had to be done, but its policy options were constrained. New Labour, elected on a strong law and order ticket, could not reduce police numbers - that was unacceptable in presentational terms.

The only option was to introduce a new cadre of lower paid, low-skill auxiliaries, known as police community support officers, with minimal pension entitlements. This new body would give the impression that there was a police presence on the streets, while a smaller core of fully trained officers would provide a response service. Because it is not regarded as real policing, constables dislike patrolling beats, despite the fact that this is what the public expect.

Over the past decade, supine management has compensated them with various "toys and fripperies, beads for the Indians" (in the words of a very senior officer at a meeting I attended in 1997), including extendable batons and Tasers. Increasingly, British policing morphed into a faux-US style of operation. Uniforms were made to look overtly military. The public were regarded, almost uniformly, as suspects, with any hint of dissent interpreted as anti-police. To this must be added the post-9/11 and 7/7 atmosphere. A succession of intrusive powers under the various terrorism acts convinced many officers that they are frontline combatants in the war on terror.

The concept of officer safety has assumed a life of its own. It started in the late 1990s with the laudable aim of designing a stab-proof vest for officers as a response to a small number of knife attacks. The concept has now moved from a defensive posture to an aggressive model. Officers are trained to be on guard against attack, to regard every situation, no matter how seemingly benign, as a threat situation. The lesson is that the public are your enemy.

That mindset appeared to dominate at the G20 protests. Video footage showing officers with steel batons raised shouting "Back off!" is a classic example of officer-safety training. Indeed, the G20 has become a tipping point. With a number of equally concerned former Association of Chief Police Officers (Acpo) colleagues, I am preparing a contribution to Denis O'Connor's review of public order policing. I know him to be a man of firm principle and I hope that he will accept the issues that we have identified.

At the core of the crisis in policing is a crisis of leadership. The only effective way to command public order situations is by visible and accountable leadership. In recent years the concept of supervision has disappeared from the lexicon of the Met. Supervisors no longer supervise. Constables refer to sergeants as "PCs with stripes"; most are addressed by their Christian names. Inspectors do not inspect anyone, as standards of appearance and behaviour at the G20 confirm. By ignoring their responsibilities, sergeants and inspectors are failing their own senior officers, but more importantly, they are in breach of the duty of care that they owe to the public. Blame must also be laid at the door of superintendents and Acpo members who claim a public order pedigree but are noticeably absent when problems arise. A rigorous reappraisal of how to supervise personnel is long overdue.

Integrity is non-negotiable. Police officers are rightly held to a higher standard of behaviour than the general public. All officers, irrespective of length of service, experience or rank need to be aware that if their integrity is flawed, they cannot remain in the service. This is not new thinking - the Police (Conduct) Regulations 2008 leave no room for doubt. The standards are binding; it would be disingenuous for any officer to claim not to know what is expected.

An audit trail can be drawn between misconduct at the G20 protests, such as concealing identity and unprovoked assault, and each standard in the regulations. The responsibility to "challenge and report improper conduct" was clearly honoured in the breach. In circumstances reminiscent of the death of Blair Peach in a 1979 anti-racism demonstration, it must be assumed that misplaced loyalty within groups such as the Met's Territorial Support Group has a bearing on the situation the force faces.

There is also a case for a programme to change the mindset of today's young officers, some of whom will be the police leaders of the 2020s and 2030s. They must recognise that the right of lawful protest is inalienable. If they cannot accept this, then perhaps we should consider looking outside the service for the senior officers of tomorrow.

david@dgilbertson.freeserve.co.uk