The consumer champion collected details of more than 2,500 experiences from passengers who suffered delays and cancellations – finding out how they rated their airline’s immediate response and handling of any subsequent complaints or claims.

The results show that in some cases passengers had the stress of facing delays or cancellations compounded by poor customer service.

In almost half (44 per cent) of all cases, passengers said there were no staff at all available to help them – and even when airline employees could be found they were not helpful in one in five (20 per cent) cases.

Only one in four people told Which? they were satisfied overall by the way their grievance was handled when they complained about a delay, while six in 10 were left disappointed.

The lowest level of satisfaction was recorded by BA passengers – only one in seven passengers (15 per cent) were satisfied with the outcome of their complaint, while three-quarters (75 per cent) were left dissatisfied.

This was considerably higher than the number of disappointed travellers with Ryanair (63 per cent) and easyJet (49 per cent).

On the plus side, British Airways passengers affected by disruption were at least able to find a member of staff at the airport in seven in ten (69 per cent) cases.

Ryanair customers were the least likely to be able to find a member of staff to assist them, with 61 per cent of passengers unable to locate someone from Ryanair.

The passengers most likely to be given assistance by staff in the event of a delay or cancellation were those who flew with Emirates (74 per cent), Jet2 (73 per cent) and Virgin Atlantic (73 per cent).

Which? found that when airline staff were on hand to assist with inquiries, they were generally helpful – passengers said staff were helpful in 80 per cent of cases overall.

This was the case for BA customers who reported helpful staff in four out of five (82 per cent) occasions, however, 18 per cent of passengers told Which? that the airline’s staff weren’t helpful.

Just over half (58 per cent) of Ryanair customers who managed to find a member of staff said that they found them helpful, while two in five (42 per cent) found them to be unhelpful.

Norwegian Air and Jet2 staff were both deemed to be the most helpful overall (92 per cent).

Naomi Leach, of Which? Travel, said: “Our research shows that it’s not just the usual suspects who are letting their customers down with poor customer service – even British Airways is falling well short in dealing with complaints when flights are delayed or cancelled.

“With the potential for widespread disruption to summer holiday travel plans in the coming weeks, airlines must ensure they have the staff and resources to deal sensitively with passengers hit by delayed or cancelled flights.”

Potential strike action by both airport and airline staff this summer could see delays and cancellations for holidaymakers.