During the Cornish May Day celebrations, nurse Laura Smallwood was hit in the neck by the costume. The costume was a large wooden circle weighing more than 50lb worn by a masked male dancer making its way through Padstow in north Cornwall.
The 34-year-old paediatric nurse died in hospital on May 4 2019, three days after the centuries-old Obby Oss festival, attended by up to 20,000 people each year.
A coroner is now set to write to the Government with his concerns about the management of large events.
Andrew Cox, the senior coroner for Cornwall, said the two Osses posed a risk to the public.
He said: “The packed nature of the streets, the fact people have inevitably been drinking alcohol and will not be paying full attention to what is happening around them, means the risk of inadvertent, unintended contact between the Oss and a member of the public is obvious.”
The inquest in Truro heard that two Osses parade through the town and each has a separate organising committee.
Mr Cox said contact between the committees and other agencies up to 2018 was “limited and far from ideal”.
He then added: “I have heard that up to 20,000 people attend the event and it cannot be right, in my view, to have an event of that size with, for example, no arrangements in place for reuniting lost children with their parents or a community first responder being able to gain access to an emergency because of a padlocked gate.
“It is only fair to note that it was a situation that had begun to improve even before these events, and it is reassuring to hear there has been a recognition of the need to move with the times and to do more.”
READ MORE: Fury as £250,000 worth of fuel stolen from Royal Navy
The inquest heard Mrs Smallwood, from Padstow, collapsed after being struck by the Oss.
A post-mortem examination found she had suffered an earlier head injury around 10 days before she died and had also been involved in a minor scuffle with a woman at the parade.
Mr Cox said Mrs Smallwood had not complained of the earlier injury and “laughed off” the confrontation.
He added: “I find that Laura had not recovered fully from the effects of this injury and so she was at increased vulnerability or susceptibility to further injury.
“I do not believe, however, that Laura’s collapse on May 1 was attributable to a delayed natural progression of the injury sustained 10 days before her death.
“In other words, I consider it far more likely that something else has intervened.”
Royal Family LIVE: Meghan shares heartbreak as Harry brings tears
Meghan cuts final ties to UK as Duchess opens up in loving statement
SNP election win the ‘End of Scotland’
Mr Cox said witnesses saw the Oss dancer stumble and the costume hit Mrs Smallwood’s neck.
He said: “I consider the proximity in time between this incident and Laura’s acute deterioration to be far more than coincidental.
“On the evidence I find as fact that the Oss struck Laura and it is far more likely than not that this caused the injuries identified at post-mortem that led directly to her death.”
He recorded a conclusion of accidental death.
On Tuesday, April 5, Oliver Smallwood gave an emotional account to the inquest into his wife’s death.
He told the inquest it was around 7pm he was informed Laura had been hit by the oss and that she’d been knocked out.
He did however state that he was told initially she was ok.
Mr Smallwood recalled walking up to Stile Field and seeing Laura lying on the ground.
He went with her in the Air Ambulance to Derriford but tragically, despite initial optimism, her condition deteriorated over the course of a few days.