A nursery nurse leapt to her death after developing a sleep disorder caused "most likely" by a swine flu vaccination, a coroner has ruled.

Katie Clack, 23, began sleeping up to 19 hours per day while her mental health deteriorated after she received the vaccine in 2009.

In 2014, Ms Clack jumped to her death from a multi-storey car park in Peterborough after the condition - narcolepsy - caused her to become depressed.

Now a coroner has ruled the receipt of the vaccine likely caused the onset of the narcolepsy.

31 million people worldwide have received the Pandemrix jab Credit: PA

An inquest in Stamford heard Ms Clack did not want the vaccine but was required to for her job.

Recording a narrative conclusion, Paul Cooper, acting senior coroner for South Lincolnshire, said studies showed there were "significantly raised odds of narcolepsy after (being given the) Pandemrix" vaccine in those aged 18 and above.

"On the available evidence on the association between vaccination with Pandemrix and onset of narcolepsy it seems most likely that receipt of this vaccine in December 2009 caused Miss Clack's narcolepsy," said Mr Cooper.

He added that narcolepsy triggers depression, though he noted the case of Ms Clack was "complex and very rare".

Katie was an energetic young woman who had just discovered her passion working with children.

Family of Katie Clack

Earlier this year, a 10-year-old boy who developed the sleeping disorder caused by the swine flu vaccine was awarded £120,000 in damages.

Across Europe, about 31 million people are thought to have received the Pandemrix jab.

Narcolepsy is a rare but serious neurological disorder that affects about 31,000 people in Britain.