Chessington World of Adventures (CWOA) has been fined £150,000 over a safety breach which saw a four-year-old girl sustain life-threatening injuries in a fall in 2012.

The girl, who cannot be named for legal reasons, fell through a gap left after an upright fence paling in the queue line for the Tomb Blaster ride was dislodged.

The park admitted the breach in a hearing late on Friday, when Guildford Crown Court heard poor maintenance meant the fence was partly rotten, posing an "obvious risk" to customers.

Passing sentence at Guildford Crown Court this morning, Judge Noel Lucas QC said the plunge was "an accident waiting to happen".

He said: "I do not regard the shoddy repairs carried out by Chessington to have been adequate. The risks were obvious."

There had been "a serious systemic failure in the administration of Chessington", he added.

No records were kept of day-to-day repairs to the fence, meaning the "pattern of failures [of palings] was not recognized", Judge Lucas said.

Surrey Comet:

CWOA was fined at Guildford Crown Court this morning

The girl's parents said in a joint statement: “The past few years have been very tough for all the family but she has got stronger and stronger which has kept us going.

“We wanted to know exactly how this incident was able to happen and how she could fall so far while queuing for a children’s ride.

“One minute we were enjoying a fun day out and the next she is fighting for her life. This should never have happened.”

In a statement read to the court, the girl’s mother said: “This was the first ride we were going on that day. We were simply moving with the queue.

“One minute she was there, and the next she wasn’t. It all happened so quickly.

“I remember running and screaming through the queue to get down. When I got there she wasn’t making any noise at all. I went in the ambulance.

“We weren’t sure if [she] was going to survive.”

Health and Safety Executive (HSE) inspector Karen Morris said: “I’m pleased that Chessington pleaded guilty. I think the fine reflects the seriousness of the offence and hopefully it will provide an explanation for the family.

“I’m pleased that [the judge] appreciated the seriousness of it and the devastating effect it has had on the family.”

Claire Howard, of Irwin Mitchell solicitors, said: “Although the HSE prosecution is now over, the civil claim continues. [The girl] still has years of difficulty ahead of her because of her injuries and the likelihood is that she may have to live with the consequences of this incident forever.”

Surrey Comet:

The 12ft drop where the girl fell

A CWOA spokeswoman said: "The resort has an excellent safety record with no previous convictions or enforcement notices against it, and every year invests significant resources in maintenance and safety measures.

"What happened to the young child was an isolated incident which we deeply regret, and from the outset we have put in place a package of support for the child and the family which will continue for as long as is required."

The park had worked with the HSE to make the ride safer, she said.