On Wednesday, British Airways passengers had their flights delayed and some even cancelled as a result of a yet to be specified IT system issue.

In total, it is reported that as many as 7,000 passengers were affected and more than 3,000 were stranded overnight as they attempted to fly back to London.

The issue originated on the IT supplier’s side and caused havoc for passengers at London’s Heathrow airport (LHR), Europe’s biggest airport.

“We are experiencing disruption to our flights as a result of an issue with some of our IT systems,” reads the official statement of British Airways on the airlines’ Twitter account. Reportedly, the British Airways passengers stranded at the airport were advised to ‘look for overnight accommodation or seek alternative travel arrangements’.

There also were reports alleging that the airline online-check in service had failed.

British Airways official statement: Source Twitter

At the time of the incident a spokesperson for Heathrow said: “We are aware that British Airways is currently experiencing an issue which is impacting their ability to provide boarding passes to some passengers. We will be working with the airline to support their efforts to resolve the issue as quickly as possible.”

The complication came just a few hours after a fire alarm at Heathrow's air traffic control tower caused a number of flight delays for several airlines. This incident was not related to the British Airways issue, according to LHR.

According to the airport, the British Airways malfunction has "impacted operation of the airfield for a short while".

British Airways experienced a similar malfunction to their IT systems in May 2017. Back then the company reported a computer meltdown that led to the cancellation of over 700 flights at the start of a busy holiday period, leaving some 75,000 passengers grounded at two London airports, Gatwick and Heathrow. At the time, the airlines promised to take steps to avoid such incidents in the future.

Heathrow was also at the center of a security scare back in 2017 after a memory stick containing sensitive information about the airport was reportedly “found in the street.”

Wednesday’s incident has also happened during the peak of the holiday season. British Airways customers waiting on updates from the carrier complained on social media of long delays and ‘nightmare service’, while being constantly moved from one queue to another queue.

On Thursday morning a spokesperson for British Airways said: “Our flights are operating today, however we expect some knock on disruption from yesterday’s combination of a temporary closure of Heathrow Airport’s air traffic control tower and a supplier system issue which affected a number of airlines.

“We are doing all we can to keep disruption to our services to a minimum, and are sorry for the disruption to our customers’ travel plans.”