Caring for children within our detention estate is a hugely emotive issue, and this is a crucial debate that I am glad the New Statesman has prompted. It's a debate that has been well led for some years by children's charities.

They convinced me that the UK Border Agency's (UKBA) treatment of children needed to become much more sensitive. That's why we've transformed our children's policy over the past two years, even legislating to impose a duty on UKBA to keep children safe from harm.

Nobody wants to detain children. So, why does it happen? As a parent myself of three small children, I have a simple motive. I insist that we keep families together and not split them up.

The sad fact is that children end up within our detention estate because their parents refuse to go home - even when an independent judge reviewing the case at first hand, or on appeal, says they have no right to stay.

Since I became immigration minister, we have tried new ways of solving this problem. For example, asking families to report to airports without detention involved. The result? Disappointing. Virtually none turned up.

Worse, some parents physically disrupt their trip to the airport by behaving violently or even harming UKBA and airport staff in front of their children. We could never reward this behaviour by simply letting people stay. It would ma ke a mockery of the courts and, indeed, of justice. Eighty per cent of families that do obey the law are out of the detention system and on their way home in less than seven days.

I would much prefer it if families returned home voluntarily and saved the taxpayer the £11,000 it costs for an enforced removal. So we bend over backwards to help families go home of their own volition. But sometimes families refuse to take this option and it's then that they find themselves within our detention estate.

I know our contract staff in removal centres provide care with the utmost sensitivity and compassion in really difficult circumstances, because I have studied the situation at first hand. When I've spent time with immigration officers involved in removing families - often young public servants with families of their own - I have seen how physically draining the job can be. That is why it is a task conducted with such sensitivity and thought.

It's why medical care at a removal centre is as good as it is on the NHS. At Yarl's Wood - where most families are housed - there is 24-hour nursing care with 14 nurses, two doctors on call day and night, as well as social workers and dentists.

It's why families have rooms that afford privacy. It's why Yarl's Wood has a nursery recently awarded three good and one outstanding rating by Ofsted inspectors, why children have access to multilingual carers, registered teachers, youth workers, internet facilities, a library and sports equipment.

I don't think we can ever stop reform to ensure UKBA does a better job. It's why I have asked for a host of pilots to test alternatives to detention (inspired, I might say, by children's charities). If they work, I hope it will become the norm.