Chessington World of Adventures (CWOA) has admitted breaching health and safety laws after a young girl fell nearly four metres and fractured her skull as she queued for a ride.

The girl, who cannot be named for legal reasons, fell through a gap in a fence in the queue for the Tomb Blaster ride in 2012, and spent four weeks in hospital after suffering fractured ribs and a bleed on the brain.

In a Guildford Crown Court hearing late yesterday the park pleaded guilty to the breach. A judge will impose a fine on Monday.

Prosecutors said poor maintenance meant a wooden fence along the queue line for the ride was partly rotten, posing an "obvious risk" to customers.

Rain water from the roof of the ride had dripped down on the fence for years, Matthew Butt told the court on behalf of the Health and Safety Executive (HSE).

Though inspections were regularly carried out, logs were not kept of repairs made to palings in the fence, he said.

One of these had given way minutes before the girl's fall, the court heard, and another woman only just saved her daughter from falling through the same gap.

The missing paling - the upright post of a fence - was found by a cleaner who alerted a team leader, but by the time the leader reached the gap in the fence the girl had already fallen.

The girl is now back in school, Mr Butt said, but is "academically behind her peers".

He added: "There is marked difference after the accident. She is easily distracted, lacks concentration and is very easily tired.

"She has a classroom assistant throughout the day."

The assistant is currently paid for by CWOA's insurers, he said.

The girl's mother was "very proud" of her daughter's recovery, the court heard, but has suffered post-traumatic stress because of the incident.

Angus Withington, defending, said park bosses felt "regret and remorse" over the accident.

He also praised the response of park staff.

He added: "There was no criticism at all made and indeed they acted with commendable speed once it was known that the paling was missing."

Workers also reacted "immediately to obtain first aid" after the girl fell, he said.

The fence is now fully inspected every two weeks.

A CWOA spokeswoman said: "Chessington World of Adventures regards the health and safety of its guests and employees as its number one priority.

"The resort has an excellent safety record and every year we invest 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.

"We have also co-operated fully with the HSE investigation.

"This showed both a rigorous inspection and maintenance regime, and evidence not only of very swift action by staff, but also that the paling was dislodged by the application of exceptional force upon it shortly before the accident.

"Nevertheless, we have worked with the HSE to put some additional measures in place, including the installation of new metal safety fencing along the queue line."