On Sunday midnight we will all cheer as the time moves from 23:59.59 to 00:00.00.

It sounds as predictable as a ticking clock. But the start and length of a year are anything but.

If you are Chinese, the New Year is still several weeks away because the Year of the Dog won’t start until February 16.

New Year 5778 (Jewish) was on September 20, New Year 1439 (Islamic) was on September 21 and December 3 or Advent Sunday was the Christian New Year. Hindus, having more than one calendar, will mark New Year in March and April.

Taking the matter further – every schoolchild knows that the academic year starts on September 1, unless you are in Scotland in which case it is in August, every lawyer will tell you the legal year starts in October and every accountant will tell you the tax year starts on April 6.

With a little bit of initiative, you could probably find a New Year’s Day for every month of the year which is good news for firework and champagne producers, but endless confusion for everyone else unless you say exactly what kind of a year you are talking about.

As for the length of a year, that is far from being automatically 365 days with a 366-day year every fourth year.

Astronomers will tell you that the astronomical year (of which they have at least three definitions) is exactly 365.something-to-umpteen-decimal-places which they calculate with much measurement of star and sun positions in the sky and consultation of a quartz crystal.

Every now and again their calculations convince them the secular year is a second out and they instruct us to adjust our clocks accordingly.

Everyone duly ignores their advice because non-astronomers are far more relaxed about the exact length of a year.

The Muslim year is 354 or 355 days, not 365 or 366, the Jewish year oscillates between 353 and 385 days, and the UK Parliamentarian year is as stretchy as a piece of elastic. In the last 20 years alone it has varied from six to 24 months.

It used to start in November, with erratic new year days in other months, often May, depending on when Prime Minsters called elections.

The current Parliamentary year started on June 13, 2017 and will last 23 months until May 2019 because 12 months isn’t long enough for the current Prime Minister.

It is only comparatively recently that the English secular year has started on January 1.

Up until 1752, that honour went to March 25, which is why events such as the execution of Charles I have more than one date. Modern accounts say he died on January 30, 1649, but those actually at the event in London, were convinced it was January 30, 1648.

That’s because Britain was literally behind the times from 1582 onwards. That year, Pope Gregory reformed Catholic Europe’s calendar after astronomers convinced him so many of their corrections had been ignored, the seasons were sliding out of their proper months.

It took until 1752 for the astronomers to convince Protestant Britain. In that year Britain deducted 11 days from the years to put the seasons back in their places, synchronise the English and Welsh date with the European date and at the same time moved New Year’s Day to match the European one which had been January 1 since 1583. Scotland  had done the same in 1600.

The taxman, however, was not prepared to lose 11 days’ revenue, so he kept on counting days disregarding their names or dates, until he reached 365 on April 5.

He then put down a year-end marker, reset himself to 0 and started counting to 365 again as he has done ever since, which is why the tax year awkwardly starts on April 6 and the financial year has to fit in with an April Fools Day start.

With all this calendar confusion, it’s reassuring to have a civil or secular year with a New Year’s date that doesn’t offend anyone’s religious or astronomical sensibilities, and a fixed length, give or take February 29. So for 00:00.00 on Sunday night may I wish you a Happy New Year 2018 AD (Anno Domini), 2018 CE (Common Era) or 67 Elizabeth II (oops, that doesn’t start until February 6).