Sam Gyimah is Parliamentary Under-Secretary of State for Prisons, Probation, Rehabilitation and Sentencing and MP for East Surrey.

Prisons are places of punishment. But they should also be places of reform. And the case for the ‘family’ in reforming offenders is clear-cut.

Stable, healthy families are the wellspring of a strong society because we all thrive when we feel safe, valued and supported. It is through a family’s unconditional love that from the word ‘Go’ we learn the big lessons of life: self-respect, self-belief – and right from wrong.

The reverse is also true. A fractured family leads to a fractured society and broken citizens. Unfortunately, too many of them will find their way to our prisons.

But while it is the state that incarcerates offenders, it is families and communities who accept them back into their midst at the end of their sentence. That means a prisoner’s family is the most effective resettlement agency we have – as the prison inspectorate, the probation service, and Ofsted all agree.

That’s not to say that families where both parents are fully engaged can’t be dysfunctional; nor is it to say that all offenders’ families are virtuous pillars of the community. But where the benefits of healthy family ties are so far-reaching, there is every reason to support them. alongside improving education and work training for offenders and tackling mental health and substance abuse problems.

Offenders are more likely to make progress in prison and afterwards if they receive consistent encouragement and support from family outside. It’s a theme reinforced by an excellent new review by Lord Farmer, who describes as a ‘golden thread’ the link between positive family ties and reducing re-offending.

Making sure this thread does not snap should be a priority for all those who want to see crime come down. Close family plays a big role in the future path an offender takes, and can have the most profound influence over behaviour. A close family gives offenders a sense of purpose and direction.

So it’s all the more vital that a prisoner returning home is neither a stranger, nor a more damaged person than before they went to prison – and that family ties are properly nurtured in the interim.

The time to work on this is from the moment an offender is sentenced to jail. To leave it any longer is to leave it too late. In the first few days and nights in prison sentence, when offenders are more likely to self-harm or, worse, take their own life, support from close family lessens the risk. As prison officers know only too well, family letters, phone calls and visits – or their absence – can make or break a prisoner’s spirit.

As time goes by, we know that a prisoner who remains in close touch with family is likely to have a stronger sense of purpose and direction, and feel more settled. Multiply this improved mood by all the men on a wing and it becomes a safer, more productive place.

There are already many prison schemes that focus on family ties. ‘Storybook Dads and Mums’, for example – a bedtime reading project that lets kids drift off to sleep listening to their absent parent reading out a pre-recorded story. HMP Parc’s ‘Learning Together’ Club encourages dads and children to do homework together, while at HMP Doncaster, a ‘Daddy Newborn’ scheme teaches men to look after their babies.

Away from these projects, I want to tell you about two men I recently met, a father and son. They’d never had a proper parent-child dynamic but were being encouraged to work on building the kind of natural relationship most of us take for granted – pretty much from scratch.

Where was this happening? In HMP Belmarsh, where both men had ended up being confined at once. The first time they were acting like a dad and a son, and it was in prison.

Unfortunately, we should not be surprised that both were behind bars. We know that boys are six times more likely to offend if they have a parent who is in prison or has served time in the past – a terrible legacy that cascades down generations. On any given day, around 200,000 children in England and Wales will have a parent in prison.

That’s why our focus should never be just the offenders, but also on those left behind as the prison van pulls away. While society rightly punishes people who commit serious crimes by removing their freedom, families are most often innocents, ‘collateral damage’. Improving family contact is better for society as a whole, given the proven link between children with a parent in prison becoming criminals themselves.

Lord Farmer’s review points us in the right direction to identify ways to improve these relationships and mitigate known problems, and decide upon the best ways to harness the influence of families to keep offenders out of trouble and out of jail.

Our efforts will be boosted by having more staff on the frontline in prisons: we are investing £100 million to increase the number of prison officers by 2,500. It will help visiting times run more smoothly. In time, the extra numbers will enable us to introduce a new ‘key-worker’ scheme in which named officers are allocated to six offenders to challenge them to reform. One particular focus will be encouraging them to maintain and develop positive family ties.

Prison works. But only if offenders are reformed, so there are fewer victims in future. Most offenders will one day be released, and harnessing the family is the best way to ensure they can function fully as members of society.