A 13-month-old girl was sexually assaulted by her father shortly before her sudden death in December 2012, a judge in Britain has ruled.

Poppi Worthington was found with serious injuries at her home in Barrow-in-Furness, Cumbria, and later pronounced dead in hospital.

Her father, Paul Worthington (47), was arrested and questioned on suspicion of sexual assault but never charged with any offence. He has denied any wrongdoing.

Sitting at Liverpool Crown Court, High Court family judge Mr Justice Peter Jackson ruled that - on the balance of probabilities - Mr Worthington "perpetrated (an) assault on Poppi".

He was guided by evidence given by medical experts in open court last month, who said they believed that Poppi had been the victim of "a...sexual assault".

Mr Justice Jackson said: "Shorn to its essentials, the situation is one in which a healthy child with no medical condition or illness was put to bed by her mother one evening and brought downstairs eight hours later by her father in a lifeless state and with troubling injuries".

"Careful assessment of the meticulous pathological and paediatric evidence has clearly established that the injuries were the result of trauma from outside the body".

"My finding (in a previous judgement) was that the father perpetrated (an) assault on Poppi...That remains my conclusion".

"Absence of evidence"

The facts surrounding the little girl's death have been kept largely private.

In 2013, a post-mortem report described cause of death as 'unascertained'.

The following year, a fact-finding civil court judgement was not made public to avoid prejudicing any criminal proceedings.

Also in 2014, Poppi's death was declared as 'unexplained' during an inquest held at Barrow Town Hall that lasted only seven minutes.

But in January 2015, the Senior Coroner for Cumbria, David Roberts, said he would ask for a new inquest.

He made his comment in a written reply to lawyers representing various media organisations, who had argued that the previous hearing, three months before, had been insufficient and therefore unlawful.

Then, in March 2015, Cumbria Police announced that no charges would be brought against anyone over Poppi's death.

The force had previously passed a file to the UK's Crown Prosecution Service for its consideration.

There is said to be an "absence of evidence" to find out how Poppi died - or prove if or how she was injured - partly because of a botched police investigation.

Items were not preserved for forensic evidence either at the family home or at the hospital Poppi was taken to. Nor was the scene at the house secured.

Poppi's mother wept in court as Mr Justice Jackson gave his fresh judgement. Poppi's father did not attend.