If you and your child’s other parent cannot agree on where your child lives or when they see each of you, sooner or later somebody will mention the C100. The C100 form is the application that asks the family court in England and Wales to make a decision about a child, and for most parents it is the first formal step into the court process.
It is a long form, and filling it in can feel like a bigger step than you intended to take. This guide explains what the form covers, when you need one, what the MIAM requirement means, what it costs, and what tends to happen in the weeks after you send it in.
What the C100 form actually is
The C100 form is the application for an order under Section 8 of the Children Act 1989. That single form covers three different orders, and you can apply for more than one on the same application.
A child arrangements order sets out who a child lives with and who they spend time with. This is the one most parents are thinking of when they talk about custody, a word the law in England and Wales stopped using decades ago. A prohibited steps order stops one parent doing something specific, such as moving a child abroad or changing their surname. A specific issue order asks the court to settle a single disputed question, for example which school a child should attend or whether they should have a particular medical treatment.
Whichever order you ask for, the court applies the same test. The child’s welfare comes first, ahead of what either parent feels they are owed, and the judge works through a welfare checklist that includes the child’s own wishes and feelings depending on their age and understanding. The court also starts from the position that it will not make an order at all unless doing so is better for the child than making none. Those principles run through every part of children law, and they are worth holding on to when the paperwork starts to feel adversarial.
When you need a C100 form, and when you don’t
You do not need a court order to agree arrangements for your children. Most separated parents never apply to court. They work out a routine between themselves, sometimes with help from a mediator, and adjust it as the children grow. Nothing about that arrangement is less valid for being informal.
A C100 form becomes the sensible route when agreement is genuinely out of reach, when one parent is being kept from seeing a child without good reason, or when a decision has to be made and neither parent can make it alone. It is also the form used when someone needs the court to prevent something happening quickly, such as a planned relocation.
Parents, guardians and anyone who already holds a child arrangements order can apply as of right. Other people who matter to a child, grandparents most commonly, usually need the court’s permission first, which is asked for on the same form. If your worry is about a child’s safety rather than a disagreement over time and routine, read our note on protecting children in family law disputes before you start, because a different route may fit your situation better.
The MIAM: the step that comes before the form
Before you can apply, you are normally expected to attend a MIAM, a Mediation Information and Assessment Meeting. It is a single meeting with an accredited family mediator who explains how mediation works, assesses whether your case is suitable for it, and signs the relevant section of your C100 form to confirm you attended.
Exemptions exist, and the main ones cover domestic abuse with supporting evidence, urgency where a child is at risk, and situations where mediation has already been tried recently or the other parent will not engage. You claim an exemption on the form itself, and the court can and does check whether it was properly claimed.
The rules around this tightened in April 2024, when changes to the Family Procedure Rules narrowed the exemptions and gave judges more room to pause proceedings so that parties can try mediation or another form of non-court dispute resolution. Parties are also expected to set out their views on resolving matters away from court. Our summary of recent changes in family law covers this in more detail, and if you are still weighing your options, the comparison between a solicitor-led route and family mediation is a useful place to start. Mediation will not suit every family, but it settles a great many child arrangements disputes at a fraction of the cost and time of a contested hearing.
court Filling in the C100 form and sending it to court
The C100 form runs to more than twenty pages. You can complete it online through the GOV.UK service for applying for a court order about children, saving as you go, or download and post a paper version. Either way you will need full details for yourself, the other parent, and every child the application concerns, along with a clear explanation of what you are asking the court to decide and why.
The court fee is £270, as of July 2026, following the fee increase that took effect on 13 July 2026 (see the Ministry of Justice announcement on court and tribunal fees). If you are on a low income or receive certain benefits, the Help with Fees scheme may reduce or remove it, and you apply for that at the same time as your application.
If you are raising allegations of harm, whether to you or to your child, you also need to complete form C1A alongside the C100. Do not leave those concerns to be mentioned later at a hearing. Setting them out properly at the start affects how the case is managed from day one, including whether special measures are put in place at court. Where abuse is part of the picture, protective orders such as a non-molestation order sit alongside the children application rather than replacing it, and there is no court fee to apply for one. Warrens’ archived guidance on domestic abuse and protective orders explains how those applications work.
Getting the form itself right matters more than people expect. A vague or overlong statement of what you want, or a section left blank, is one of the most common reasons an application stalls before it has properly begun. Fixed-fee help with drafting is available if you would rather not do it alone: Family Law Service offers a Form C100 completion service for exactly this.
What happens after you apply
Once your application is issued, the court sends the details to Cafcass, the body that advises the family court on children’s welfare. A Cafcass officer carries out safeguarding checks, which involve contacting both parents by telephone and making enquiries with the police and the local authority. They then send a short safeguarding letter to the court before the first hearing.
That first hearing is called the First Hearing Dispute Resolution Appointment, or FHDRA. It usually takes place a few weeks to a couple of months after issue, depending on how busy your local court is. Its purpose is to identify what is actually in dispute and to see whether agreement is possible with the court’s help. A significant proportion of cases are resolved at or shortly after this hearing, sometimes by consent order, without ever reaching a contested final hearing.
If matters cannot be resolved there, the court sets directions: statements to be filed, perhaps a fuller Cafcass report under Section 7, and a further hearing. Cases that run the full distance can take the better part of a year. That timescale is one of the strongest arguments for exhausting every other option first. If you have a Cafcass call or meeting coming up, this guide to what to expect at a Cafcass meeting is worth reading beforehand.
Editor’s Note, 2026
This article is part of an archive preserved from the original Warrens Family Law website. The firm no longer takes on new instructions under this name.
For modern help with child arrangements, court forms and family law advice, please visit FamilyLawService.co.uk.
Mistakes that slow an application down
A few patterns come up again and again. The first is writing the application as an attack on the other parent. Judges read hundreds of these, and a form that catalogues grievances rather than explaining what a child needs tends to work against the person who wrote it.
The second is asking for the wrong order, or for several orders when one would do. If your real concern is a proposed house move, a prohibited steps order addresses it directly. If it is the school run and alternate weekends, that is a child arrangements order.
The third is skipping the MIAM without a valid exemption, which simply sends the application back. The fourth is underestimating what happens next. Applying to court hands the decision to a judge, and judges rarely give either parent everything they asked for. Going in with a realistic sense of what a workable arrangement looks like puts you in a far better position at the first hearing.
Weighing it up
The C100 is a practical document, not a declaration of war, and there are situations where applying is plainly the right thing to do: where a child is being kept from a parent, where safety is at stake, or where a decision has to be made and cannot be made any other way. In those cases, do not let the length of the form or the fee put you off.
Equally, it is worth being honest about whether the disagreement in front of you really needs a judge. Court is slower, more expensive and more stressful than the alternatives, and any order it makes still has to be lived with by two people who will be co-parenting for years. Whichever route you take, the more clearly you can describe what your child needs, the better it tends to go.