More than one in seven trains were late in the 12 months to the end of September, new figures show.
Just 85.9% of trains met the rail industry’s punctuality target, the Office of Rail and Road said.
That is down 2.5 percentage points on the previous 12 months and is the worst performance since December 2005.
Trains are recording as late if they arrive at their terminating station more than five minutes behind schedule, or 10 minutes for long-distance journeys.
The proportion of trains which failed to arrive at their final destination within 30 minutes of the timetable or were cancelled rose by 1.1 percentage points year-on-year to 4.6% in the 12 months to the end of September.
Performance on the rail network was hit by a number of issues in this period, including the chaotic introduction of new timetables in May and a spell of freezing weather as the Beast from the East hit the country in February and March.
Engineers also faced track defects caused by the summer heatwave.
Robert Nisbet, regional director at industry body the Rail Delivery Group, said: “Every minute counts for our customers and we apologise to them for the unacceptable disruption over the summer.
“We have one of the most congested railways in Europe and this summer it has been stretched by an unprecedented heatwave and, in some parts of the country, the introduction of the May timetable.
“To ease pressure so customers get the railway they want, we’re delivering record investment in infrastructure but this can’t come at the cost of today’s punctuality.
“That is why we’re working hard to learn the lessons from May, starting with the introduction of the December timetable on Sunday.”
The cost of many rail season tickets will increase by more than £100 next month as average fares go up 3.1%.
Labour’s shadow transport secretary Andy McDonald said: “The travelling public have already suffered a miserable year of delays and cancellations so it’s outrageous that rail users will be hit with another above inflation fare rise in January.
“At the very least, fares should rise no higher than the Consumer Price Index (CPI) and be frozen altogether on routes that were impacted by the timetable chaos.
“The inability of the Government to deliver a reliable rail service is playing havoc with people’s work and family lives.
“Labour will take the railways into public ownership, prevent above inflation fare rises and deliver the reliable services that passengers and our economy needs.”
Transport Secretary Chris Grayling has previously insisted that fare rises can only be tied to CPI rather than the higher RPI figure if the switch is also made for rail workers’ pay rises.
On Tuesday the Transport Select Committee published a scathing report which said Mr Grayling should have been more proactive in preventing the timetable disruption.
The committee called for swift reforms to restore passengers’ trust in the railways and said the “chaotic roll-out” of alterations to services across the country should be the catalyst for “genuine change” for people who rely on the network.
The Department for Transport has launched a review by Keith Williams to consider all parts of the industry.