The small hand tells you the hours and the big hand tells you the minutes, but the traditional clock face no longer tells many pupils anything at all.

A teacher, giving a presentation at a conference in London, has said that many pupils in Years 9, 10, and 11 are only able to tell the time if provided with a digital clock.

She told participants: “It is amazing the number of students I am coming across in Year 10, 11 and in sixth form who do not know how to tell the time.

“We live in a world where everything is digital. We are moving towards a digital age and they do not necessarily have analogue watches anymore and they have mobile phones with the time on.”

The teacher was speaking at a conference held last month by PIXL (Partners in Excellence), a partnership of more than 2,500 schools, sixth forms and alternative providers.

Her claim was backed up by delegates from a range of secondary schools, who said that it was common for GCSE candidates not to be able to read an analogue clock.

A number of Twitter teachers agreed, with some pointing out that their pupils were unable to understand clock chimes.

The Year 1 national curriculum programme of study for maths requires that pupils learn to tell the time on an analogue clock, and to be able to draw hands on a clock face marking the hour and half-hour.

However, writer and primary-education expert Sue Cowley suggested that this means very little 10 years after pupils have left key stage 1.

Certainly, many teachers recognised the practical difficulties created by horological illiteracy among GCSE candidates.

Others, however, argued that digital clocks ensured that no pupil was left out.