When sibling rivalry takes a serious turn

'My son tormented his baby sister endlessly - it was like living with an abusive partner'

The jealousy started before she was born.

As soon as our daughter was big enough to show in her mother’s womb, her two-year-old brother started acting up. He developed an insatiable desire for Mummy, from first thing in the morning and throughout the night.

Eating and sleeping regressed. The tantrums started in earnest.