As an ex-teacher at non-faith schools, it is perfectly acceptable to ask for children not to take part in any religious praticises (e.g one-off group prayer at assembly) if it is important to you
Two points- firstly we don't have "non faith" schools in the UK.
We have non denominational schools, and these are required by law to deliver collective worship of a christian nature.
This means that had teachers have the freedom to deliver as much or as little religious indoctrination as they choose.
In some schools it is not so easy to remove a child for a prayer- and indeed why should they be removed?
In practice that child will be doing nothing in a side room, stigatised by peers, feel awkward.
My children went to a non dom state primary.
The head was very religious.
He chose religious staff.
Assemblies were an important part of the school community.
A typical Friday morning woud run thus:
- Welcome and short prayer.
- Round up of events of the week.
- Hymn.
- Awards- Star writer, Best Buddy award, etc.
- Short talk of a recent class trip.
- Prayer- often local clergy member.
- Birthday.
- Song of worship- Jesus is my Super Hero or similar.
So remove a child from the christian bits?
Class was similarly peppered with mentios of god, bible readings etc ( I worked as a class helper)
Before you say move scho0ols- we lived in a rural community, work and family close by. The only other school within 30 miles ( also state non dom) was silimarly run by a rabid christian head.
Not so easy to "opt out".