When is it ok for a baby to sleep alone with a toddler?

[hellymelly]

We co-sleep still with our three year old and the baby who is 13m.I remember reading that it was a danger to a baby to sleep alone with an older child,so I have the baby sleeping next to me on the sofa until I go to bed,while our older daughter just goes to sleep in the big bed.Eventually the idea is that we will put them in their room together,but at what age is it safe to let them go off to sleep next to each other in bed,is the baby big enough yet? anyone else co-sleep with more than one?

I didn't co sleep, but my dds shared a room from when dd2 was 12 months (in a cot) and when she went into a bed at 2, it was two singles pushed together to make a big bed with dd1 who was just over 3, and we had no problems then.