Public policy goes in waves. We like to think that each wave is based on evidence, analysis and logic but probably at least as much are fads, politics and a desire to try something new. That may not be a bad thing. Any system needs shaking up now and then and what some see as reinventing the wheel can look like progress and common sense to others.

Currently, we are in a wave of domestic policy thinking that repudiates much of what happened to public services since around 1979.

You can see this story in the latest NLGN offering. It looks forward to a new approach it calls the ‘Community Paradigm'. You can see a slightly more retro version in some of what comes out of some ‘Corbynite' thinking, often with genuflections to some great older days via proposals for nationalisation, the scrapping of SATs, the end of contracting.

Clearly, the fears and realities of ‘producer capture' that were so strong in the past, have faded when compared to the clear and apparent problems that arise when you follow alternative strategies. This is tied to the excitable movement of community wealth building, highlighted in Preston, but happening in other areas, too.

There are also moves to change the relationship between the council and statutory sector and its citizens, seen in the Wigan Deal and the co-operative council movements. Perhaps, more surprisingly, you can also see it in the way the Conservative Government has pulled away from outsourcing.

All of this is interesting and useful. Sometimes it is presented as revolutionary, a big attack on what is loosely termed neo-liberalism. That clearly suits the narratives of those searching for new models and wanting to define themselves primarily by contrasting themselves to whatever happened in the past.

Sometimes it is just a response to reality. This is true for private prisons and of outsourcing – which has given us the recent debacle of the Carillion collapse to add to problems with companies like G4S, Serco and Interserve.

Challenging existing policies and paradigms is something we should always want. In social policy, where we are dealing with individual families and communities, there are no absolutes and what works in one place, at one time, in a certain context, may not work in another. Providers, whether in-house or outsourced, become entrenched over time and the systems and power structures they create need periodic shaking up. Meanwhile, technology enables new approaches and new research challenges our assumptions. There is a sense in which this is all progress.

I like to think that some of the current change is due to a genuinely new level of understanding that in many areas effective public services must be much more about relationships, not just transactions. The relationship between the frontline person and the service user is crucial, and it is likely to get squashed if there is too much emphasis on delivering contracts, too much profit motive in play or too much leaning on payment by results.

We must look out for unintended consequences of these new trends as well. The ideas that are being railed against now were by and large sensible solutions to the issues policy-makers faced at the time. Being too enthusiastic to do away with what came before, even if parts of it have become very problematic, can have unintended consequences.

Worse still, total rejection of previous thinking means we can't learn the lessons it has to offer us. Without doing this, we run the risk of making the same mistakes.

Perhaps the ebb and flow of certain ideas and trends is inevitable, but we should make sure we are moving in a positive direction, and for that we need to understand where we are, but also how we got here.

Dan Corry is chief executive officer of NPC, a think-tank and consultancy on third sector issues. He is a former Treasury and Downing Street economic adviser