Analysis of Office of Rail and Road (ORR) data found the cancellations score for all operators during the four weeks to January 7 was 8 per cent.
That was double the proportion from the previous four weeks, and represents the poorest reliability in records dating back to April 2014.
Avanti West Coast's latest cancellations score was 18.9 per cent, which was one of the highest ever recorded for any operator.
The Department for Transport (DfT) responded to the figures by saying it is working with train companies to ensure there is "swift recruitment and training of new drivers", but Labour claimed services are "in crisis".
Cancellations scores reflect the percentage of services that are either fully or part-cancelled, with part-cancellations counted as half a full cancellation.
The impact felt by passengers is even worse, as the statistics do not include services removed from timetables as late as 10pm on the previous night.
This controversial process known as p-coding, which last week the ORR ordered operators to stop using when they axe services due to not having enough staff or trains in the right locations, is what happens ahead of strike days.
But a rail industry source noted the latest reliability figures cover a period when operators were badly affected by an overtime ban introduced as part of industrial action, and stated there are difficulties resuming services on the day after strikes.
Avanti West Coast runs trains on the West Coast Main Line between London Euston and Glasgow Central with branches to Birmingham, North Wales, Liverpool, Manchester and Edinburgh.
The operator – a joint venture between FirstGroup (70 per cent) and Italian state operator Trenitalia (30 per cent) – was given until April 1 by the DfT to improve its services when it was awarded a short-term contract extension in October last year.
It slashed its timetable in August last year to cut short-notice cancellations after a sharp decline in the number of drivers voluntarily working on rest days for extra pay, amid industrial relations disputes across Britain's railways.
There was a huge uplift in planned services when a new timetable was introduced on December 11, but this was followed by poor reliability.
Southeastern, whose services were taken over by the DfT in October 2021, had the second worst cancellations score for the four weeks to January 7 with 12.2 per cent, which was its most on record.
It was followed by Govia Thameslink Railway, which consists of Southern, Thameslink, Great Northern and Gatwick Express, and TransPennine Express, which both had a score of 11.9 per cent.
A DfT spokeswoman said: "We are working closely with train operators to ensure disruption is kept to a minimum and long-term solutions are put in place, including the swift recruitment and training of new drivers."
Labour's shadow transport secretary, Louise Haigh, said: "Thirteen years of Conservative failure has left the country with second-rate infrastructure and rail services in crisis.
"Ministers continue to hand over millions in taxpayer-funded performance bonuses to failing operators.”