Council social services bosses have apologised to a mother-of-three who says she went through "five months of absolute hell" after limits were unfairly placed on when she could see her children.
Lawyers representing the woman say Cumbria County Council staff wrongly restricted the amount of contact she could have with the youngsters.
Solicitor Stephen Cardinal, who is based at law firm Irwin Mitchell, said the woman's human rights had been infringed and described what had happened as "hugely worrying".
The council said its handling of the case had not been "good enough", with a spokesman adding on Wednesday that improvements had been made.
"The woman has a history of mental health problems and in September 2016 was seen by psychiatry experts following a deterioration in her condition," said an Irwin Mitchell spokesman.
"Although it was recorded that she posed a low risk to both herself and her children, it was decided at a child protection conference a month later that she should only have contact with two of her children under the supervision of her ex-husband.
"As her third child was in hospital at the time, she was also only permitted to visit in communal areas, with the restrictions continuing until further reassessments were undertaken.
"Despite her disputing the restrictions on several occasions, they remained in place until February 2017 when her case was heard in a family court and they were removed.
"The council has now apologised to the woman formally and has admitted that children's services should not have advised that her contact with her children had to be supervised. The council also admitted that there was delay in bringing her case to court."
Mr Cardinal said the woman had suffered "extreme distress".
"This was a hugely worrying situation where we believe that the council's behaviour has significantly infringed on the human rights of our client," he added.
"This whole experience led her to suffer extreme distress and upset and affected her relationship with her children. It is simply unacceptable and we are delighted she has now had an apology from the council."
The woman, who lawyers say cannot be named in media reports, said: "The restrictions placed on my contact with my children meant that I experienced five months of absolute hell.
"The whole ordeal was a nightmare."
A council spokesman said: "We have apologised to her for how this matter was handled, it was not good enough. We have since improved how we respond to situations like these."
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