The Scottish Government’s embattled Named Person scheme faced renewed criticism last week, when one of its leading proponents dubbed it unworkable.
Liberal Democrat leader Willie Rennie, previously a strong supporter of the plan, said his party now questions its implementation altogether.
His U-turn pours further scorn on a scheme which was recently mauled by experts in law and education.
The Scottish Government is trying to revive its plans after central elements of the Named Person scheme were ruled to be unlawful by the UK Supreme Court.
Ministers have drawn up a code of practice, designed to guide Named Persons on sharing sensitive data about children.
However, the code has been rubbished by legal experts and teachers appearing before Holyrood’s Education Committee in recent weeks.
Mr Rennie said the Named Person scheme has “lost the confidence of parents and many professionals.
“There has been significant mission creep in the way it will work, with practitioners, out of fear that they will be criticised for not complying with the law, going beyond what their professional judgement would dictate.”
Labour MSPs have also voiced their disquiet over the code, saying it will encourage “defensive practice”.
A spokesman for the No to Named Persons campaign (NO2NP), backed by The Christian Institute, said:
“The Named Person scheme is holed below the water line and rapidly sinking under a tsunami of condemnation from experts and those expected to implement it.”
He added: “The draft code has been attacked on all sides by information watchdogs, teachers, lawyers and health visitors.”
Responding to criticism of its plans, a spokeswoman for the Scottish Government said it will “ensure successful implementation”.