A woman left paralysed after being "catapulted" from her new bed during sex is suing the bed firm for at least £1 million in damages.
Claire Busby, of Maidenhead, Berkshire, suffered a serious injury to her spine when she fell from the super king-size double divan as she shifted her position.
The 46-year-old claims the bed was in a "defective state" at the time of her accident and is taking legal action against Berkshire Bed Company, trading as Beds Are Uzzz, which supplied it.
Judge Barry Cotter, sitting in the High Court in London on Monday, was told the "central issue" in the case is whether there were defects with the bed and whether Ms Busby's "tragic injuries" were caused or contributed to by them.
The firm denies liability for Ms Busby's injuries and is contesting the case, arguing the bed was properly assembled.
The court heard the bed was one of five delivered to Ms Busby's then home, Rosewood House in Ockwells Road, in August 2013 when she was renovating the property.
Ms Busby, who used to work in the property industry, was injured a week after the bed's delivery while having sex with her partner John Marshall.
She told the court she was kneeling in the middle of the bed performing a sex act when she decided to move position and "swung her legs" from underneath her, before laying back on the bed.
At that point, she claims, the bed gave way and she toppled off the end, landing on her head.
She said: "I spun around, I put my hand down and then I felt like I was catapulted off the back of the bed.
"My head hit the floor, I fell to the side and then I heard like a spring in my body snap, it felt like."
Her sister, Natalie Busby, told the court that when she went to the property after the accident she noticed there were "two feet" missing from the bed.
She said they did not discuss the matter until much later because Ms Busby was in such poor health.
She said: "Claire wasn't in any fit state to be having a conversation, at one point she had two heart attacks in 24 hours.
"It was touch and go whether she was going to make it."
Ms Busby alleges that the two divans which made up the base of the bed were not properly fastened together and two "gliders" - or feet - were missing from the end of the bed, creating a height difference between one end and the other.
Her barrister Winston Hunter QC said she expected the mattress to support her weight as she lay back on the bed, but that it failed to and she continued moving "backwards and downwards".
He told the court: "It is the claimant's case that the point at which she left the bed is precisely the location where the different height of the two divans was at its maximum.
"It represented the area where the mattress was most likely to 'fall away' due to the fact that it was partially unsupported."
Mr Hunter said it was "accepted that the particular circumstances of the accident are unusual", but it was enough for there to have been "some foresight of some loss of balance in the use of the bed" for the firm to be found liable.
Lawyers for the bed company argue it was properly assembled at the time of delivery and that, even if the two gliders were missing by the time of the accident, that would not have caused the bed to lose balance in the way suggested by Ms Busby.
Neil Block QC, for the firm, said: "It is overwhelmingly likely that, whatever her actions, they were too close to the edge of the bed and she simply lost balance and toppled backwards."
The hearing continues.