I just had a phone call from ds's teacher to tell me that he had picked up another child and thrown them onto a mat. During reading time, no obvious provocation apparently. Earlier he had hit someone and she had heard another child say 'you see x that's why no one likes you' 
He has had behavioural issues like this before but I thought things had got better. His teacher thinks he his struggling now that work at school is getting more focused.
Their way of handling it before was to stop him having playtime, though I put an end to this when I found out as that is the last thing he needs is less exercise.
I have no idea what to do and I don't have that much faith in the school tbh, it is a church school and quite academic and old fashioned. We need to move hi, but easier said than done (London)
Any ideas?