A huge thunderstorm that led to the closure of Heathrow airport last week led to British Airways losing some 11,000 pieces of luggage, it has been reported.

According to The Guardian newspaper, the carrier still has 7,000 pieces of luggage and is in the process of returning them to their rightful owners across the world. The newspaper reports that 100 staff have volunteered to help solve the problem, which could lead to the carrier paying out large sums in compensation.

The violent storm led to more than 130 flights being cancelled; passengers were generally put on to other flights, The Guardian reports, but in many cases it was not possible to transfer luggage quickly enough.

A spokesman is quoted as saying: “It has been a very difficult time and all we can do is apologise.”