Alcohol, drugs and self-harm: the cost of parents divorcing

Nearly a third of Londoners from broken homes said they witnessed violence when their parents broke up.

The survey of 2,000 people also found nearly a fifth felt they had been "used" by a parent to lie to the other with 17 per cent saying they were told to spy on a parent.

Some children in the capital were so traumatised that more than five per cent considered suicide and nearly twice that number attempted self-harm.

The study, commissioned by solicitors' Mishcon de Reya to coincide with the 20th anniversary of the Children Act, supports calls for reform of family law services.

Sandra Davis, from the law firm, said that despite the intentions of the Act to protect "caught in the middle kids", children are still suffering because their parents use them as "emotional footballs" in court proceedings.

Ms Davis said: "Not only are warring mothers and fathers damaging their children, they are costing the taxpayer millions which could be spent so much more constructively.

"We need to take parents out of the legal arena and do more to encourage them to make use of parenting classes. This approach is working wonders in the US."

It cost £151million in legal aid last year for parents battling over divorce and child custody cases. However, only £13million of that was spent on mediation to avoid court proceedings.

Ms Davis called on the Government to set up parenting classes for separating couples who would otherwise claim legal aid.