Slaughterhouses in England will have to install CCTV as part of government plans to monitor animal welfare.
Under rules being phased in over the next year, Food Standards Agency vets will be able to ask to see footage of all areas where livestock are held.
Slaughterhouses found to be failing welfare standards could face a criminal investigation or lose staff licences.
Environment Secretary Michael Gove said the proposals would make the UK a "global leader on animal welfare".
Currently, keepers of animals bred for meat must meet animal welfare laws and codes of practice, which cover the treatment of livestock including how they are fed, housed and transported, as well as how they are killed.
Abattoirs in England must meet welfare regulations, with separate rules in Scotland, Wales and Northern Ireland and additional EU regulations.
The government has said it plans to increase standards for farm animals and domestic pets in England by updating these statutory animal welfare codes.
Breaches would result in a welfare enforcement notice, the suspending or revoking of staff licences or referral for a criminal investigation.
The first codes to be revised will cover chickens bred for meat, followed by laying hens, pigs, dogs, cats and horses over the course of the next year.
New codes were needed to reflect modernising medicines, technology, as well as the latest research and advice from vets, the government said.
Mr Gove said: "We have some of the highest animal welfare standards in the world and the actions I am setting out today will reinforce our status as a global leader.
"As we prepare to leave the EU, these measures provide a further demonstration to consumers around the world that our food is produced to the very highest standards."
FSA chairwoman Heather Hancock said the watchdog supported compulsory CCTV in abattoirs, since voluntary adoption by slaughterhouses had reached a "plateau".
She said: "We look forward to the introduction of a comprehensive requirement for using, accessing and retaining footage from CCTV in abattoirs.
"We see CCTV as an invaluable management tool for business owners to help with compliance with official controls and to improve animal welfare standards across the industry."
British Veterinary Association (BVA) president Gudrun Ravetz said the mandatory CCTV in all areas of slaughterhouses was "essential" to safeguarding animal welfare.
"We are particularly pleased to see a commitment to official veterinarians having unrestricted access to footage, which the BVA has been calling for," he said.
"Vets' independence and unique qualifications help ensure that the UK will continue to have the highest standards of animal health, welfare and food safety."