Most childcare agreements end calmly, with notice. Once in a while something happens that means you can't carry on for even one more day, and your contract needs to say clearly what those situations are. You'll sometimes see this called gross misconduct, but that's an employment term. In a childcare contract, call it ending without notice for a serious breach.
When it's justified
Childminders most often need to end a place straight away when a child's safety requires it, when someone is threatening, abusive or violent towards you, your family or anyone in your setting, when fees are still unpaid after the notice for non-payment has run out, or when information in the agreement turns out to be deliberately false. A serious or repeated breach of the agreement can also justify it, and so can a breakdown in the relationship that stops you caring for the child properly.
Why not "for any reason I decide"?
It's tempting to write that you can end the agreement without notice for any reason you like. Under the Consumer Rights Act, a term that lets one side end the contract at will, with no notice, is likely to be unfair and unenforceable, which would leave you with no protection at all. Naming specific grounds is what makes the clause hold up.
Give a warning first
For anything other than safety or abusive behaviour, give a written warning and a reasonable chance to put things right before you end the agreement. Where a child's safety is at risk, you can act first and explain afterwards. That keeps the clause firm and fair at the same time.
Safeguarding comes first
If you're ending a place because of a safeguarding concern, follow your safeguarding procedures before anything else. Ending the contract doesn't end your duty to report the concern to children's social care, or to call the police if a child is in immediate danger. Depending on what happened, you may also need to tell Ofsted or your agency.
The family's side
A fair contract also lets the family end it straight away if you can't meet your duties under it, for example if you stop being registered. Giving them that right makes your own clause easier to defend.
GoChildmind includes this as a standard term, with named grounds, a written warning for anything short of a safety concern, and the family's matching right to leave.