Although we would doubtless all like to regard ourselves as pragmatic and able to deal effectively with whatever circumstances are thrown our way, certain situations can still stop us in our tracks.

An unexpected bill (or, even worse in these days of constant digital connection, a costly scam) can be a real shock to the system.

The fact that some of these ultimately turn out to be official mistakes does not lessen the impact of such a nasty surprise.

What it does do is cause us to question the efficiency of the organisations involved and whether anything can be done to prevent a repeat of the error in future.

These are all points which were at the heart of a recent BBC website article considering the experiences of dozens of parents who believed themselves to have been on the wrong end of dealings with the Child Maintenance Service (CMS).

The article explored how some of the individuals had been involved in court proceedings with the Service, had child maintenances wrongly calculated and even seen five-figure sums taken from their bank accounts, apparently without warning.

Some of the complaints cited by the BBC related to historical maintenance arrangements which had already been concluded years before cash deductions were made.

They echoed the sort of cases which I and my colleagues at Hall Brown Family Law have been confronted with over recent years.

It caused me to think about why such instances might happen and how they could be avoided.

By way of a starting point, it is perhaps worth reminding ourselves of what the CMS is and what its responsibilities are.

The Service was introduced in December 2012 as part of the then government’s child maintenance reforms.

It replaced the Child Support Agency (CSA) and was designed to make the calculation and collection of child maintenance more efficient.

Figures released by the Department for Work and Pensions (DWP) at the end of March showed that 1.1 million children are covered by some 800,000 CMS arrangements between 720,000 parents who were unable to agree child support between themselves.

When the CMS becomes involved, it calculates maintenance according to a range of factors, including a paying, non-resident parent’s income, how much time they might spend with a child subject to such arrangements, whether they look after other children and the expenses incurred in doing so.

If a paying parent’s income exceeds £156,000 a year gross, then the receiving parent can also apply to a court for a ‘top-up’ after first obtaining what is known as a maximum assessment from the CMS.

Furthermore, the CMS has the power to deduct sums due from a paying parent’s wages, bank accounts, benefits or pensions if they are not paid in line with its decisions.

As the BBC article and the DWP figures illustrate, a significant proportion of CMS’ assessments later have to be revised. Either parent can apply for what is known as a Mandatory Reconsideration if they disagree with the original assessment.

The DWP data shows, in fact, that in the last 12 months, the CMS received 92,700 requests for a Mandatory Reconsideration – 15% more than the previous year.

A significant proportion – 21,400 (or 23%) – of applications for a Mandatory Reconsideration in 2025 were successful.

A Mandatory Reconsideration can be requested within 30 days of a CMS assessment being made but, as the BBC article outlines, any amounts deducted by the Service can be withheld pending the outcome of an appeal.

It is a situation which can compound difficulties that might have led to the original breakdown of a relationship between parents, preventing both from fulfilling what is surely the objective of providing effective care for their children.

Given that the level of maintenance payments is reviewed on an annual basis (or sooner, if there is a change in circumstances), it presents the potential for repeated problems too.

However, in my opinion, the answer lies in preparation and clear communication.

Although it might not necessarily seem like a priority for receiving or paying parents, keeping a record of agreed child arrangements can avoid later disputes or discord.

It is especially true when we consider that many such responsibilities are not rigidly enshrined in court orders but are rather more fluid.

A diary of practical arrangements helps both parents explain the actuality of their situation to the CMS. There are now such useful resources as parenting apps with shared calendars to assist.

Likewise, being absolutely transparent with the CMS when it comes to income and expenses related to child arrangements will be very useful when it comes time for annual assessments, let alone if an objection or complaint is raised by the other parent.

Due to the sheer volume of cases which it deals with, the CMS does not necessarily have an easy task.

Whilst many parents subject to assessments made by the Service do comply with what is expected of them, large numbers do not. The most recent figures show that in 2024, the amount of child maintenance arrears stood at £682.1 million – more than double the figure just five years before.

Perhaps unsurprisingly, the CMS has its critics.

Last summer, the House of Commons’ Work and Pensions Committee opened an inquiry into what it described as “concerns over how it [the CMS] calculates payments, how it handles people who have sometimes been through long ordeals, and over its enforcement”.

That announcement came just three months before the Lords’ Public Services Committee published its own separate study into similar issues.

The report called for Government to reform the CMS, with one of its key recommendations being an improvement in how the Service explained its mission and interacted with parents it engaged with.

Any resulting changes may be some time off, so it makes good sense for parents to be on the front foot and prepared for possible questions from the CMS or their former partners.

Keeping an up-to-date record of exchanges, payments, earnings and caring responsibilities may not completely forestall problems but they can help resolve whatever matters arise and allow those caught in the CMS’ crosshairs to get on with the essential if rather more mundane, everyday tasks which might be more commonly associated with parenting.