The budget Dublin-based airline was given a refund rating of just 47% in a survey by consumer group Which?

More than one in five customers who booked a Ryanair flight that was either cancelled or that they could not board due to the COVID crisis said it took more than a month to receive a refund.

"Ryanair is the most awkward airline to deal with that I have ever come across. It seems to be proud of being difficult," one customer said.

Read more: Ryanair flight makes emergency landing on way from Manchester after 'fire breaks out on board'

Meanwhile, British Airways was ranked the second-lowest of five airlines for refund satisfaction, scoring 63%.

Some people reported spending hours on hold after telephoning the firm, only to be hung up on, while others said they were continuously passed between different BA departments.

Jet2.com ranks highest

Jet2.com scored the highest satisfaction rating among short-haul carriers for refunds, with 84% of respondents saying they were happy with how their claim was handled.

One passenger said: "The pandemic has seen Jet2 shine. Its standard of customer care exceeds that of any other low-cost airline."

Most flights were cancelled following the beginning of the pandemic in spring 2020 when demand for travel collapsed.

Affected passengers were entitled to cash refunds within 14 days under consumer law, though many airlines were overwhelmed by requests.

Millions of customers also struggled to obtain refunds for flights that went ahead, but they could not use them due to COVID restrictions.

Last October, Which? surveyed more than 1,124 members of its online research panel who had experienced a disrupted flight since March 2020.

'Terrible customer service'

Which? Travel editor Rory Boland said: "Ryanair's consistently terrible customer service has made it a fixture among the worst performers in our surveys for many years - but the airline plumbed new depths with its handling of COVID refunds.

"BA's reputation also deservedly took a battering when it took a hard line on refunds for passengers who could not travel because they followed government health guidance.

"Many passengers will not forget how they were treated by companies during the pandemic.

"COVID could still cause disruption to international travel, so we would advise travellers to book with operators that have flexible booking policies and a record of treating their customers fairly."

Ryanair appeal rejected

The survey results came shortly after Ryanair failed in its bid to overturn a court ruling that it cannot avoid paying compensation to passengers affected by industrial action.

Droves of customers were affected when flights were cancelled following a series of walkouts by pilots and cabin crew during the summer of 2018.

The airliner claimed it was exempt from awarding compensation because the disruption was due to "extraordinary circumstances", but the Civil Aviation Authority (CAA) disagreed and took legal action against the firm.

BA admits 'we can do better'

In response to the Which? findings, British Airways said: "We're proud that we were the first UK airline to offer customers the flexibility to amend their plans at the beginning of the pandemic, by providing vouchers that they can use up to September 2023.

"If we cancel a flight we always contact customers to offer a range of options including a full refund. We've issued more than 4.2 million refunds and have dealt with more than 3.3 million voucher requests to date."

The statement added: "However, we know we can do better and we're working hard behind the scenes, upgrading our phone systems and recruiting more people to deliver a better and faster customer experience that we know our customers deserve.

"We never take our customers' loyalty for granted and appreciate their patience as our teams work around the clock to support them."

Sky News has reached out to Ryanair for comment on the research.