what shall I do

I think you have an obligation to speak out. Perhaps you could invite the little girl's mother over for coffee while the girls play. She may be looking for someone to speak to.

Schools should have child protection systems in place. You could tell a teacher your suspictions, or ring the NSPCC anonymously. It sounds as if the family want to keep the girl out of her father's way. They may be very grateful if somebody intervenes. Could you invite the mother and brother round for a cup of coffee when the father is at work?

You MUST SPEAK OUT,

The mothers English is not great and we do not want her to think that the child has been speaking out of turn, thereby making a situation worse I shall speak the her headmistress first thing Monday morning Thank you for your comments.
Do you think it would be acceptable to invite her brother back for tea as he is 11 and would be the only boy.

Don't delay in informing either police, social services or NSPCC. if you know a child is being assaulted, you have a moral obligation to help that child. How would you feel if he was hospitalised, or worse, when it could have been prevented? Please report it. Pick up the phone. There is always a 24 hour service to respond to risk to children.

You can only ask him....he might be glad to have a change.

The mothers English is not great and we do not want her to think that the child has been speaking out of turn, thereby making a situation worse I shall speak the her headmistress first thing Monday morning Thank you for your comments.
Do you think it would be acceptable to invite her brother back for tea as he is 11 and would be the only boy.

I echo everyone's comments, mugnanny. Please don't keep this to yourself. You can easily ask the young lad along for tea as well - he can always make an excuse not to come, but it might make him feel not so alone. However, don't feel as if the children are your responsibility - your responsibility is to pass on your fears about their safety.

mugnanny

I agree with others, you cannot keep this to yourself now you have this information. You know that if anything happened you would find it very difficult to come to terms with I am sure as you must be an empathetic person. The 'never on our doorstep' comment and all that.

It may be cowardly to suggest but I would definately tell someone anonymously as I would be concerned that the father could turn on you and that could be a position that you most certainly do not want to become embroiled in. He is after all a coward of a man but equally bad tempered and has a loss of any decency and would not care what he does. Be careful.