The Fold at 01:00: Designing UK Schedules for the Night the Clocks Go Back

On Sunday 25 October 2026, British Summer Time ended at 02:00 BST and clocks returned to 01:00 GMT. For most households the change was a minor inconvenience: one extra hour in bed, a few appliances blinking on the kitchen display. For shift workers, transport operators, payroll teams and anyone managing a medication schedule, the same night contained a harder problem. The hour between 01:00 and 02:00 happened twice, and most UK schedules did not say so.

That is not a curiosity of the calendar. It is a design failure with practical consequences. A rota that treats the night as a straight line can undercount or overcount hours worked. A timetable that shows 01:30 without an offset can leave a passenger unsure whether the train has already gone. A medication chart that uses wall-clock time can make a four-hour interval ambiguous at precisely the moment clarity matters. The repeated hour is a data integrity issue, and information design should treat it as one.

Why the repeated hour is a design failure, not a curiosity

Most calendar and timetable graphics are built around the idea that time moves forward in a single direction. A day is drawn as a line from left to right, or a column from top to bottom. Each hour appears once. That convention is so strong that designers rarely question it. When the clocks go back, however, the local civil day is 25 hours long. The line folds back on itself, and the graphic keeps drawing as if it has not.

The usual workaround is a small asterisk, a footnote, or a verbal warning in a separate document. These are weak remedies. An asterisk depends on the reader noticing it, finding the note, and interpreting it correctly. In a busy hospital corridor or on a station platform at midnight, that is too much to ask. Accessibility guidance already tells us not to rely on colour alone or on tiny symbols to carry essential meaning. The same principle applies to time.

A folded strip, not a clock face

A more honest visual grammar begins with a folded strip. Draw the night as a vertical sequence of 25 hourly slots rather than 24. At the point where the clocks go back, insert a fold marker between 01:00 BST and 01:00 GMT. The two 01:00 slots should be adjacent but visually distinct, and both should carry their offset in text. The first might read 01:00 BST; the second, 01:00 GMT. No reader should have to infer which is which from position alone.

A second column can show elapsed time from the start of the period. This is particularly useful for rotas and medication schedules. Clock time answers the question what time is it; elapsed time answers the question how long has passed. On the night the clocks change, those two questions have different answers. A shift that normally spans nine hours may span ten. A four-hour interval may cross the fold. Showing both columns prevents the graphic from quietly choosing one interpretation on the reader's behalf.

Colour can help, but it should not be the only signal. Use a change of line style, a repeated label, or a pattern fill as well as a hue shift. On a phone screen in low light, a subtle shade difference between two 01:00 blocks is likely to disappear. Text labels and clear boundaries survive.

Where the hour hides in UK operations

Rail timetables are a useful test case. Departure boards and printed leaflets usually list clock times, and an 01:30 departure on the night of the change is ambiguous unless the operator publishes the offset. A better approach is to show 01:30 BST and 01:30 GMT explicitly, or to suppress the repeated hour from consumer-facing displays and direct passengers to a note that explains why. The worst option is a clean-looking table that leaves the ambiguity in place.

NHS rotas present a similar problem. A night shift that starts before the change and ends after it may contain an extra hour of elapsed time. The rota should say whether that hour is paid, banked, or treated as ordinary clock time. A small folded strip beside the shift entry can do this without turning the rota into a legal document. It also gives ward managers a shared visual reference when questions arise later.

Payroll systems often handle the arithmetic correctly but display it poorly. A payslip or dashboard that shows hours worked without showing the fold can look wrong to the person reading it. A simple two-line summary, one for clock time and one for elapsed time, is more defensible than a single figure with no explanation. The same principle applies to household calendars: a reminder for 01:30 on the night of the change should say which 01:30 is meant, or it should be scheduled in elapsed time instead.

Labels, legends and the test of the phone screen

Any graphic for the clock change should pass a simple test: can it be understood on a phone screen, at night, by someone who is tired and in a hurry? That means large text for the critical labels, strong contrast, and no reliance on hover states or footnotes. It means writing BST and GMT in full at least once, rather than assuming the reader knows the abbreviations. It means giving the repeated hour a visible boundary, not a decorative clock icon that implies a seamless circle.

For digital calendars, the underlying data should carry a time zone identifier as well as a local time. The graphic should reflect that discipline. A label such as 01:00 Europe/London is not elegant, but it is unambiguous. Where space is tight, a legend can explain that the first 01:00 is BST and the second is GMT, provided the legend is adjacent to the graphic rather than buried at the end of a document.

A short checklist for UK communicators

• Show the night as 25 slots, not 24, with a visible fold at the repeated hour.
• Label both occurrences of 01:00 with their offset: BST and GMT.
• Separate clock time from elapsed time wherever duration matters.
• Use text and pattern as well as colour to distinguish the two hours.
• Test the graphic on a phone screen in low light before publishing.
• Give calendars, rotas and timetables a plain-language note that explains the fold.

The clock change is a recurring event, but the design problem is not seasonal. It is a test of whether our schedules respect the difference between what the clock says and what actually happens. At WHP Information Graphics, the aim is to make complex information clear, one chart at a time. The night the clocks go back is a good place to start, because the complexity is real, the audience is broad, and the fix is largely a matter of drawing the fold honestly.