The service, which launched a year ago, attracted 207 complaints per 100,000 journeys – more than any of the 23 other companies apart from Caledonian Sleeper, which has had historically high complaint rates.
The Lumo rate for April to June is more than twice that of East Coast Main Line direct rival LNER, with 84 complaints per 100,000 journeys, which was also 9 per cent down on the same period last year. Lumo’s ticket and refund policy generated the most complaints, followed by punctuality and reliability. However, its complaint rate was down from 276 between January and March.
The Office of Rail and Road (ORR) figures showed Caledonian Sleeper’s complaints rate over the period was up by 31 per cent on a year ago to 396, but down from 449 in the year to March. Nearly a quarter of Sleeper complaints were about on-board facilities and almost a quarter about the upkeep and repair of the trains.
Its new fleet has suffered chronic electronic glitches and water supply problems since being introduced three years ago, although managing director Kathryn Darbandi insisted this summer the issues had largely been ironed out.
Glasgow-London operator Avanti West Coast had the third highest complaint rate, at 161, which more than doubled on last year.
Lack of space and facilities on its trains prompted the most complaints.
The firm was given a six-month extension to its contract by the UK Government this month to prove itself after ministers said service levels had been “unacceptable”.
The biggest increase in complaints among any operator was at TransPennine Express, which connects Edinburgh and Glasgow with northern England. Its rate more than trebled to 83 per 100,000 journeys, with punctuality and reliability accounting for a quarter of complaints.
By contrast, ScotRail, most of whose journeys are much shorter than the cross-Border operators, saw its complaints rate fall by nearly a quarter to 32 per 100,000 trips.
Punctuality and reliability were its passengers’ biggest gripes, accounting for 17 per cent of the total.
The other cross-Border operator, CrossCountry, saw its complaints rate fall by more than a third to 19, led by ticket and refunds issues.
Robert Samson, senior stakeholder manager at watchdog Transport Focus, said: “Passengers complain about services to show their priorities aren’t being met.
“While we understand some issues are beyond operators’ control, if passengers are given an improved journey experience this would help in reducing complaints. It’s important that operators provide punctual and reliable journeys that passengers can depend on.”
The ORR said comparisons with last year for individual train operators should be treated with caution because the number of complaints and passengers substantially increased from a low level as Covid restrictions were eased. A Lumo spokesperson said: “We are taking our ranking in this report very seriously and will take action accordingly. Comfort, service and reliability are hugely important to us. With a relatively low number of services compared to many other operators, a higher proportion of our trains are affected by rail works and other disruptions that affect our punctuality.”
A Transport Scotland spokesperson said the Caledonian Sleeper "continues to deliver above the benchmark targets for both performance and passenger satisfaction”.