Awful behaviour in 2 year old boy

[Babycoz]

My little 2 year old boy is normally a delight but he has been an absolute terror since we came back from our holiday 3 weeks ago. He is really naughty around other children - and has taken to biting pinching hitting pushing scratching etc. This behaviour is unprovoked ie not when fighting over a toy although that can bring it on too. I'm at my wits end and feel nervous of taking him to others peoples houses, to playgroups and after he kicked a small boy even to the park. We have tried the naughty step but he just gets up and as I have a 4.5 year old girl and a five month old baby I cant always be on hand to keep him there. Now we are trying time out in the pushchair but he laughs at us and when we let him out he does it again straight away. We are making every effort to praise him when he is good. I feel so bad for the other children and feel I am being judged as being a v poor mother and soon people will stop inviting us to play. Please any advice - I just want my lovely little boy back!!

[poshtottie]

My ds has been similar but mostly to me. Yesterday I had to leave my shopping in Waitrose and take him home. I have been keeping a behaviour diary and my HV was here two hours today.

With my ds it seems to be attention seeking or we have pinpointed times when his behaviour is worse, eg: tired, hungry, or he has had sugar.

Is it boys? I don't seem to see this in girls at all.