And the chance of Mrs Christine Walton or her husband Martin injuring a four-month-old boy in their care had to be 'virtually inevitable' before the council which registered her as a minder could be held accountable.
So claimed Mr Edwards Faulks, for the council, in the action brought by the mother of the injured baby, Mrs Cora Dowling, against the Waltons and the local authority.
Mrs Dowling seeks compensation over the severe brain damage suffered by her son, Thomas, allegedly whilst in the Waltons' care in September 1989. Mrs Dowling, 33, had moved from Chesterfield, Derbyshire, just weeks before to her mother's home in Chaucer Road, Ashford, Surrey, after her relationship with Thomas's father, John Harrison, broke down.
Mr and Mrs Walton, also of Ashgrove Road, Ashford, strongly deny any blame for Thomas' injuries. They have highlighted Mrs Dowling's admission that she was 'overcome with depression' and had begun proceedings to have Thomas fostered a week before he suffered brain damage.
Surrey CC also strongly denies liability. Mrs Dowling claims the council's Nursery and Childminding Services officer, Mr Peter Bodycomb, told her he was 'happy' for Thomas to be minded by Mrs Walton. And she says she was not told that another baby, Simon Hewitt, was injured while in the Walton's care just two months earlier.
Mr Bodycomb disputes her version of the conversation.
Mr Faulks told the court that a mother of one of last victims of Yorkshire Ripper Peter Sutcliffe had sued the police over their alleged negligence in not arresting him before he attacked her daughter.
That action failed in part because the judges ruled that if the police were not 'immune' from such liability, it would inhibit their primary function of protecting the public, he said.
'The success of such an action could cause that function being done in a detrimental defensive manner. It would divert police manpower away from their main function.
'Many of these observations are relevant to the facts in this case. There is a temptation to rehear the case conferences in this case with the benefit of hindsight.
'Police and local authorities do make mistakes - childminding resources are scarce enough, for them to think they would by liable to be sued would not be in the public interest.'
The telephone call between Mrs Dowling and Mr Bodycomb ought not to 'saddle the council with liability they would not otherwise have', he said. 'For Mr Bodycomb to tell her he had to put the telephone down and he couldn't speak to her because he might be sued would be highly undesirable.'
Counsel told the judge it was not enough for the grave injury suffered by Thomas to have been reasonably forseeable because an earlier baby had suffered mysterious afflictions.
'If it were forseeable that Mrs Walton - if you find that - deliberately caused injury to Thomas, for a third party like the council to be held responsible it would have to be virtually inevitable.'
The trial continues.