The incident occurred last month, shortly after the non-stop BA-35 service to Chennai had taken off.
The Boeing 787 Dreamliner was inspected on the tarmac once it landed and was found to have sustained “between 42 and 46 holes”, the Telegraph reports.
The aircraft was grounded while further tests were conducted and was unable to complete its scheduled return leg the following day.
It subsequently remained in Chennai until July 29, when it returned to Heathrow without passengers and was re-examined at Heathrow.
Following a series of thorough checks it has now returned to duty.
British Airways confirmed the lightning strike had occurred, but said that it did “not recognise the description of the damage", and that at no point were passengers at risk.
"We apologised to customers and rebooked them onto alternative services after our flight from Chennai to London was cancelled on Sunday following a technical issue," a British Airways spokesperson added.
"The aircraft was inspected by our highly qualified engineers before returning to service.”