A zoo has been fined £255,000 after one of its employees was killed by a Sumatran tiger.

Sarah McClay, 24, was pounced on in the keeper's corridor of the tiger house at South Lakes Safari Zoo in Dalton-in-Furness, Cumbria, on May 24, 2013.

The company, whose sole director David Gill founded the zoo, entered guilty pleas at Preston Crown Court on Wednesday to contravening health and safety laws on the day of the tragedy.

The company was fined an additional £42,500 after it had also pleaded guilty to other health and safety law breaches when a zoo keeper fell from a ladder while preparing to feed big cats on July 18 2014.

It must also pay £150,000 prosecution costs.

Sentencing, Mr Justice Turner said "it should not have been possible" for the tiger to gain access to where Miss McClay was working.

He said: "But as a substantially contributory cause as a result of a door-closing mechanism failure, it did.

"The result was as tragic as it was foreseeable. The tiger attacked and Sarah was fatally injured."

The judge said the incident the following year involving a ladder was "an accident waiting to happen".

South Lakes Safari Zoo Ltd admitted that on or before May 24 2013, it failed to ensure the health, safety and welfare at work of employees - including Miss McClay - arising out of and/or in connection with the keeping of big cats.

It also pleaded guilty to failing to ensure that persons not in its employment on the above date were not exposed to risk to their health and safety.

The pleas came ahead of a scheduled trial, and the prosecution offered no evidence against Mr Gill 55 - who had faced individual charges on the same allegations.

Miss McClay suffered "unsurvivable" multiple injuries and was airlifted from the scene to hospital where she was formally pronounced dead.

In September 2014, an inquest jury in Kendal ruled in a narrative verdict that Padang the Sumatran tiger got to Miss McClay by entering two open internal sliding gates within the tiger house and then an open door from the tiger's "dark den" that led on to the corridor.

Systems were in place at the park to ensure that animals and keepers remained apart at all times through indoor and outdoor compartments connected by lockable self-closing doors.

The animal was supposed to never have access to the corridor, but the male tiger walked through the dark den door to where Miss McClay, from Barrow-in-Furness, was carrying out cleaning and feeding duties in the house.

Two internal sliding gates were also open, which allowed Padang and his female companion, Alisha, to move in and out of a light den and a dark den to the outside enclosure.

The company accepted its risk assessment did not address sufficiently the risks arising from a failure to maintain the dark den door - labelled in court as "the last line of defence" for the animal keepers.

The company said "a more proactive maintenance and inspection regime" should have been in place to ensure that the door functioned efficiently and that its self-closing mechanism worked properly.

Miss McClay had worked full-time at the zoo, formerly known as South Lakes Wild Animal Park, since March 2011.

She initially looked after birds before in 2012 she worked with "Category One" animals such as the Sumatran tigers and jaguars that were kept in the tiger house designed by Mr Gill.

In victim personal statements read in court, Miss McClay's mother, Fiona McClay, from Linlithgow, Scotland, said she felt responsible for her daughter's death because she had "encouraged her to take a full time position at the zoo".

She added: "It feels like my own life ended when my child died."

Miss McClay had been in a relationship since 2005 with boyfriend David Shaw and he said he had found it hard to live without her.

She was "the soul" of the house they shared and she had designed, and he could not bear to move some of her possessions.

Brother Stephen described her as "a positive person, honest, caring and witty", whose death had left "a big hole in my life", while sister Lucy said she did not know how to enjoy Christmases and birthdays as her sister "always took the lead and was the organiser".

In mitigation, Ben Compton QC said his client wanted to express its "deep regret" at the death of Miss McClay.

He said: "For those working at the zoo, including David Gill, the horror of that day will never be forgotten as well nor the memories of her.

"People who worked with her said she was young, intelligent, bubbly, competent, loved her job and was one of the most popular people there. Good at everything she did."

He submitted that the court should take into account the financial position of the company and the benefits it brought to the region.

It had opened in May 1994 and in its infancy was a success story with 55,000 visitors in the first year.

By 2013 those numbers had grown to 275,000 per year with a most recent turnover of £3 million annually.

The zoo employed 100 people and was "a valuable asset to the surrounding communities in terms of employment and bringing in much-needed tourism", said Mr Compton.

It also offered free school visits and had an established overseas charity programme to help safeguard rare and endangered species.

He said it would never be known exactly what happened on the day of the tragedy as a fellow employee told police the sliding gates to the outside enclosure - "the first two lines of defence"- were closed when she left Miss McClay shortly before the attack.

Mr Compton said the zoo accepted that it had to failed to check that maintenance had been carried out on the "third line of defence" - the dark den steel door leading on to the keeper's corridor.

"Things have now changed and a more sufficient maintenance regime has been put in place," he said.

The zoo also admitted it had failed to ensure members of the public were not exposed to risk of a big cat escaping from the tiger house - with limited views to identify a cat in the corridor before seeking to gain entry.

The company also pleaded guilty to failing to ensure the health, safety and welfare at work of its employees in 2014 when keeper Yasmin Walker fell from an unsecure ladder as she attempted to fix meat to a pole for feeding the tigers.

She suffered a fractured collarbone, together with cuts and bruises, but Mr Compton said the system had now been "completely redesigned" and Ms Walker continued to work at the zoo and was a valued employee.

Mr Justice Turner said that no value could be placed upon the life of Miss McClay who he said was "clearly loved" by her family who had found her loss "hard-hitting".

He said: "This is not just a death which happened in a way that was clinical and completely instantaneous. This was a death which was particularly shocking."

The judge said he was following sentencing guidelines in setting the penalty amount and added that it could be said in mitigation on behalf of the zoo that its keepers go through a formal training schedule and that safety was a high priority.

He said the zoo was regularly inspected and those inspections were "broadly speaking in part, satisfactory" and also carried some positive comments.

The court heard the zoo - licensed by Barrow Borough Council - was inspected by Defra (the Department for Environment, Food & Rural Affairs) four days before Miss McClay's death.

Outside court, the McClay family said they did not want the zoo to close but said it should not stay open if it could not prove itself safe.

The victim's mother said: "This (the sentencing) was about safety. This was about ensuring this isn't going to happen again.

"This was about telling the public at large that an animal could have got out into the open space, that was the most important point of this."

Mrs McClay added: "We can't function yet with a member of our family missing. We have got to learn to do that and we haven't got to that stage yet.

"The guilty plea was a step forward knowing that someone else was responsible."

Mr Shaw said: "We understand that with it being a company it was always only ever going to be a financial penalty.

"But I think it is reasonable to give out the impression not just to South Lakes but to zoos across the country that they really need to be sure that they are not just giving lip service to health and safety but they are giving all their employees the best chance to keep themselves safe and doing everything they can to put proper systems in place which are safe."

Fiona Hahlo, from the zoo's lawyers Reynolds Porter Chamberlain, said: "As has been said in court, Sarah was an enthusiastic, caring, dedicated and valued member of the zoo's animal staff and she is greatly missed by all those who knew and worked with her.

"The judge recognised that to a very considerable extent that safety was a priority at the zoo. It remains a priority.

"The judge noted the positive remarks by those inspecting the zoo and the commitment and enthusiasm of the zoo's management

"He recognised that the zoo provides a substantial amenity in the Barrow area which gives much-needed opportunity to local educational establishments.

"He recognised the zoo's work with schools, its free access programme for children and its international conservational efforts.

"Lessons have been learned and the zoo continues to prioritise safety for staff and visitors."

Mr Gill, of Furness View, Broughton Road, Dalton-in-Furness, made no comment as he left court.

In March the zoo announced the death of Padang due to "welfare complications arising from his age".