A plane bound for New York had to return to Heathrow Airport after a laser was shone at the cockpit.
The Virgin Atlantic flight doubled back as a "precautionary measure" after the co-pilot reported feeling unwell following the incident, the airline said. Police said they were trying to find the source of the beam.
According to a BBC report, 15 crew members and 252 passengers were on board during the incident that took place around six to seven miles west of Heathrow.
A Virgin Atlantic spokeswoman told the Press Association : "The VS025 travelling from London Heathrow to New York JFK flight has returned to Heathrow as a precautionary measure due to a laser beam incident.
"The safety of our crew and customers is our top priority and we apologise for any inconvenience to those on board.
"All customers will be offered overnight accommodation and we will get them on their journey as soon as possible. We are working with the authorities to identify the source of the laser that caused the return of the aircraft to Heathrow."
One passenger told the BBC: "Probably about an hour into the flight we had a tannoy, and it said the second pilot had been shot in the eye with a laser during take-off, and we were going back to Heathrow."
A message on the airline's flight status website added: "Following this incident the First Officer reported feeling unwell. The decision was taken by both pilots to return to Heathrow rather than continue the transatlantic crossing."
The Metropolitan Police are investigating the incident.
In 2010, shining lasers to "dazzle the pilot" became a chargeable offence and in the UK, fines from around £100 to £300 have been imposed on perpetrators.
On Twitter, several users branded the offender as an "idiot."