What to do?

[Firsttimemummy33]

My twelve month old enjoys being at his childminders and being around the older children but won't have anything to do with the other baby who is there. Whenever he's around he cries and clings to the cm. When he's not there he's absolutely fine. Is this a normal phase of development?

When he is there without that child, he may be the only young child and thus get lots of attention from CM and older children. With another young child there, he gets less attention and so demands more attention. Sounds natural to me.

Jealousy? Yep, perfectly normal.