The claim was made by social worker Pamela Campbell at the trial of Rachael Martin, the 15-month-old's mother who - along with her former partner Barry Michael McCarney - denies charges linking them to the baby's death in December 2009.

Barry McCarney, age 33 and from Woodview Crescent in Trillick, is accused of murdering the baby girl and with sexually abusing her and inflicting grievous bodily harm.

Rachael Martin, aged 27 and from Main Street in Kesh, is charged with failing to protect her daughter from the unlawful act that caused her death and with wilfully neglecting her in a manner likely to cause unnecessary suffering.

Baby Millie was first taken to Co Fermanagh's Erne Hospital in a lifeless state. She was then transferred to the Royal Belfast Hospital for Sick Children where she died on 11 December, 2009 from severe injuries to the brain.

She was also found to have serious spinal injuries, plus older rib fractures.

Ms Campbell said that as the day wore on, talking to the distraught Martin and her mother Margaret Graham, "the penny seemed to be dropping" and they began "looking back over the past few weeks".

The social worker said both mum and daughter "became angry ... calling him [McCarney] names" while at another stage "they swore about him".

Later, she said that "they were both extremely distressed and very angry ... that someone could have done this to Millie ... they were extremely distraught and going over things".

Ms Campbell said they complained that recently when they went to pick Millie up, she appeared "to be sore around the ribs ... and that they should have picked up on this".

She added that they also told her of an occasion when baby Millie had a bump on her head, and McCarney had allegedly said that "she must have hit her head against the cot ... they were wondering what he must have done to keep her quiet".

Martin and her mother also allegedly told her that, having thought over the past weeks, other "instances had happened that they should have queried more ... they were blaming themselves for not having checked more on Millie".

Asked by defence QC John McCrudden if it had seemed as if mother and daughter hadn't linked what happened to Millie as child abuse, she added: "They seemed to be blaming themselves for not having done so."

During her evidence, the social worker was at pains to point out that she "can't stand over" what she was told, as she "wasn't there" to witness any abuse and was only reporting what she was told.

Mrs Campbell said that after "the terrible news was given that Millie was gone" both Rachael and Mrs Graham were very distressed and crying, with Rachael pleading for Millie to be kept on the ventilator.

"Rachael just wanted her to be kept going," the social worker said, adding that "both were crying, saying they could not believe this had happened".

The trial continues.