CCTV images have been released of three men suspected of being involved in a protest that saw cockroaches and locusts released into branches of the Byron burger chain.

Demonstrators targeted two of the restaurants on July 29 after it emerged that the company conspired with the Home Office to trap their own illegal workers in an immigration sting – meaning they escaped a potential £700,000 fine.

Scotland Yard said a group of men released the insects onto the floor and in the men’s toilets at Byron on St Giles High Street, Holborn, before moving on to another branch in High Holborn and setting the pests free there.

Two of the three men police want to speak to about the locusts and cockroaches which were released in the two branches

The third CCTV image that was released today

The restaurants had to be cleared of customers and closed while the insects were dealt with.

One of the suspects, dubbed Man A, is dark-skinned, medium to heavy build, and was unshaven with thinning hair. He was wearing a bulky hooded anorak, brown shoes and blue jeans, and was carrying a rucksack.

Another, Man B, is thin and dark-skinned, and was unshaven with long hair that was tied back. He wore thick-rimmed glasses and a black tracksuit with white stripes along the arms, and carried a bag or satchel over his shoulder.

Man C is also thin and dark-skinned, with short hair and a short beard. He was wearing a brown blazer, blue shirt and light grey or beige trousers.

Anyone with information can call the Met’s Public Order Crime Unit on 020 8246 0076, or Crimestoppers anonymously on 0800 555 111.