A mystery contractor who chainsawed an ancient oak in north London for the Toby Carvery restaurant chain has been identified by the Guardian, prompting more questions about the incident.

The unauthorised partial felling of the 500-year-old oak a year ago on Friday in Whitewebbs Park, Enfield, prompted widespread public outrage and questions in parliament.

Mitchells & Butler Retail (MBR), which owns Toby Carvery, claimed it was advised by its contractor that the work was necessary for safety reasons as the tree was diseased. But numerous experts, including an investigator from the Forest Commission, found it was healthy and showed little sign of needing to be felled.

Until now the identity of the contractors involved, who were photographed using vans without company logos during the work, has been kept under wraps.

The Guardian has seen documentary evidence showing the work was undertaken by Ground Control, which describes itself as “a leading maintenance business and biodiversity expert” and has a turnover of £190m.

Ground Control agreed to remove the tree for MBR which the former said was necessary to protect a public area, citing a large split in one of its main branches, documents show.

Dr Ed Pyne, a senior conversation...