A Cumbrian MP has called on the RSPCA to launch a new criminal investigation into animal deaths at South Lakes Safari Zoo.

Barrow and Furness MP John Woodcock has referred the death of Nero the lion to the RSPCA in the hope the organisation will consider mounting a new criminal investigation following the airing of the BBC2 documentary Trouble at the Zoo .

The hard-hitting programme, filmed after zoo bosses invited the BBC to the park, showed how Nero the lion died after being fed meat contaminated with barbiturates.

Last April RSPCA officers, along with Barrow Borough Council, launched an investigation after an autopsy list emerged charting the cause of death for hundreds of animals kept at South Lakes Safari Zoo.

It revealed animals had died of hypothermia, emaciation and infighting due to overstocked pens.

But last month the RSPCA confirmed it had concluded the investigation amid improved conditions and new management.

Mr Woodcock said: "It was deeply distressing to see the way Nero the lion died and the suspicion of the contaminated meat raises clear concerns of a continuing culture of neglect which may be putting other animals at risk.

"The entire zoo inspection regime needs to be overhauled but in the meantime I am asking the RSPCA formally to investigate the damning circumstances exposed in this documentary.”

Veterinary experts and state-appointed zoo inspectors laid the blame for the catalogue of animal welfare breaches listed in the autopsy report at the door of the attraction's founder David Gill who was subsequently refused a zoo licence by Barrow Borough Council.

The authority went on to award a licence to Cumbria Zoo Company which is now responsible for running the site.

Confirming the conclusion of its investigation last month, the RSPCA said: "In light of changes made in the zoo in terms of management and the efforts being made to improve conditions, we have decided to draw this investigation to a close.

"Since the zoo has been under new management some changes have been introduced to improve the welfare of animals and we hope they continue to improve standards for all the animals."