A mum claims she was terrified after her children were "not strapped in properly" when they went on an upside-down ride at Hull Fair.
Liz McCollin said daughter Jessica, 13, and son Joshua, 12, were not properly secured when they went on the 40 metre Vertigo ride.
The same evening, Monday, , Airmax 360 at the fair.
Liz told Hull Live that she and husband Kev, 56, believed neither of their children's seat belts had been properly fastened.
The 44-year-old mum claims she heard a "clanking" sound as the pendulum swung over their heads, and believes this was their children's seatbelts.
She said: "I was filming it to show my mum, and every time they went past I could hear his clanking sound.
"I said to my husband 'can you hear a clicking when they go past' and, his face, he just said 'it's the belts, they're dangling down', and I was like 'oh my god.'
"As soon as we realised that the safety belts were hanging loose and had not been clipped in we ran over to confront the staff and it was as the ride was stopping.
"He [Kev] confronted him [the fairground worker] and grabbed the clips and he [the fairground worker] denied it and said 'we've just undone them.' He was waving his arms about and denying it.
"We were both shaking, it was so scary. I just wanted them off and to be safe."
Although the ride has an over the shoulder restraint, the seatbelt is designed to keep the bar in place when the ride is moving.
Mrs McCollin said her son Josh had told her he realised his belt was not fastened when he saw it spin between his legs, but he was unable to reach for it because the ride had already started.
The mum said she is speaking out to warn other parents, and she has also emailed the Health and Safety Executive to report the incident.
She also believed the concerns of her and her husband were not taken seriously by the staff operating the ride after she reported it to the cashier.
"She asked which guy it was and then yelled to him to be more careful, she said 'what are you doing?'
"You need to take more care' but they all looked blankly at her. It's disgracefully shocking.
"Kev said 'we're wasting our time speaking to them' so we just left, it was just a joke. It was horrifying."
The mum said her children were left terrified afterwards.
"We left the fair after an hour feeling sick and all in shock and the children petrified. We just didn't want to be there. It's disgraceful.
"They clearly got them on and off as quickly as possible and forgot, it was only their two belts which had not been fastened."
It comes after a 21-year-old woman was flung from the Airmax 360 ride, also on Monday night.
The woman was seen hurtling through the air after the bar on her carriage "failed" just minutes into the ride starting, falling about 15ft and hitting a teenage boy as she crashed into the neighbouring Sizzler ride.
The HSE is investigating the incident which happened at around 7.30pm.
Garry Leach, who is chairman of the Showmen's Guild said it is difficult to comment on what happened with Jessica and Joshua, because he has not been made aware of the incident.
He said: "We have had no reports what so ever of anything like that so I can't comment on something that I know nothing about."
