This information comes from an analysis of Civil Aviation Authority (CAA) data conducted by the PA news agency.
The analysis revealed that the most delayed route was Gatwick to Bangalore, with flights averaging a delay of over 80 minutes across 50 departures.
Rory Boland, editor of consumer magazine Which? Travel, described Air India’s performance as “completely unacceptable”.
The airline said the disruption was “primarily due to factors beyond our control”.
Guernsey-based Aurigny Air Services had the second-worst punctuality record for UK departures last year, with an average delay of 31 minutes and 12 seconds.
It was followed by Turkish low-cost leisure airline SunExpress (29 minutes and 36 seconds) and Air Portugal (25 minutes and 12 seconds).
Irish carrier Emerald Airlines recorded the best performance last year with UK departures delayed by an average of just 10 minutes and 30 seconds.
The analysis took into account all scheduled and chartered departures from UK airports by airlines operating more than 2,500 of these flights last year. Cancelled flights were not included.
The average delay for all these airlines was 18 minutes and 18 seconds, down from 20 minutes and 42 seconds in 2023.
Air India was acquired from the Indian government by Tata Group in January 2022 after racking up billions of pounds of losses.
The airline’s UK operations are at Birmingham, Gatwick and Heathrow, with routes to a number of Indian cities such as Delhi, Mumbai and Bengaluru.
Data from aviation analytics company Cirium shows the airline operated 56% more flights from UK airports last year compared with 2019.
This is projected to rise to 90% this year after increasing flight frequencies on several routes in March.
Aviation consultant John Strickland said there has been “a lot of work going on to put the airline back on track” after it gained a “poor reputation” for delays and cancellations.
This was partly caused by a lack of funds to purchase spare parts for aircraft, leading to some of its fleet being grounded.
Mr Strickland said: “They’re coming out of this period of malaise pre-the Tata takeover, and now have to put in work on their engineering, manpower, spare parts holding, all those factors.”
He said some of Air India’s promotion of its new Airbus A350 first class product has focused on the quality of its service.
He noted: “You can have great meals and a great crew, but fundamentally you’ve got to operate an airline which is as punctual and reliable as possible.
“That’s definitely a work in progress for them.”
Rory Boland, editor of consumer magazine Which? Travel, said: “These latest delay figures will come as no surprise to travellers, who can find themselves paying sky high amounts for air fares and in return receiving unreliable services.
“Air India had an average delay of 45 minutes. This is completely unacceptable.
“It’s time for airlines to get their act together and start delivering the service their customers are paying for.”
A spokesperson for Air India said: “During 2024, Air India’s flights to and from the UK experienced occasional delays, primarily due to factors beyond our control.
“Proactive operational initiatives like self-check-in, baggage drop and automated boarding process have ensured smoother airport touchpoint experience and faster turnaround of aircraft, boosting on-time departures.
“The deployment of the new Airbus A350 and upgraded B787-9 aircraft on some of the UK routes has also helped enhance punctuality of our flight operations.
“Over the first three months of 2025, Air India’s on-time performance has seen significant improvement on our direct flights from the UK to India, which also reflects on our NPS (customer satisfaction) scores.”
Depending on the distance of the route and length of delay, passengers booked on flights from UK airports that are running behind schedule are entitled to assistance such as a reasonable amount of food and drink, a means to communicate and overnight accommodation if required.
Passengers may also be able to claim compensation of up to £520 from the airline if the reason for the delay is deemed within its control, which could be a fault with the aircraft or pilot sickness.
CAA head of consumers Anna Bowles said: “We expect all airlines operating in the UK to uphold high standards of service and reliability.
“While the majority of airlines have made progress in reducing delays, with the average falling, delays can cause significant disruption and inconvenience to passengers.
“Delays occur for many reasons, and we fully expect that airlines minimise the impact by providing timely information and upholding passengers’ rights when it applies.”
