Why on earth does the tax year start on the 6th of April
Why, becuase Julius Caesar got his sums wrong. Haven’t you ever wondered why the 6th of April was the start of the tax year, did you think a civil servant at the treasury woke up one day and went “I have such a cool idea, lets start the financial year on the 6th of April”.
That’s right the day burned into every accountants diary, the start of the UK tax year all because Julius Caesar got just couldn’t add up the days when decreeing that all the provinces in the Roman Empire should follow the same calendar in 45BC.
OK it was 45BC and he wasn’t that far out, Caesar set the Julian Calendar to run for 365 days but his year was 11 minutes and 30 seconds out as he wasn’t quite exact on how long the Earth took to orbit the sun. And to be fair, for several hundred years most Romans really didn't notice it. Tough It wasn’t without problems different people in the Empire applied a different date to the same day.
But as the centuries marched on this 11 and half minutes a year did eventually make a big difference and the Julian Calendar was now 10 days shorter than the solar calendar.
It was 1582, Pope Gregory stepped in and introduced the Gregorian Calendar. It was a revalation, the year went from 365.25 days to 365.2425 days, ok it wasn't that much of a revaltion but that cut of 10 minutes and 48 seconds and meant the calendars were almost aligned with the solar year.
So whats that got to do with the UK tax year. Only a few of the countries moved to the Gregorian Calendar from the start, including Italy, Spain, and Portugal. Britain carried on with the old Julian calendar which meant New Years day was 25th March and that was the start of the tax year, yes back then the 25th March was the start of the year, it was also known as Lady Day.
Finally, to come into alignment with the other countires in 1752, King George II agreed to change the British calendar to the Gregorian one. It took almost 200 years but it was needed so we just chopped a few days out. We literally skipped 11 days, Wednesday 2nd September was followed by Thursday 14th September. Everyone was happy. Well, everyone except the Treasury.
Fear of losing tax revenues
The Treasury was worried about losing 10 days of tax revenues when the calendar changed, so they moved the tax year end to April 4 and the start to April 5 to avoid the loss. that worked perfectly well for a few decades, but caused a problem on leap years, which have 366 days instead of 365.
The crunch came in 1800, which was a Gregorian leap year but not a Julian one. Once again not wanting to lose out the Treasury stepped in again to stem a day’s loss of tax revenues and moved the tax year forward another day and so in 1800, the tax year officially ended on April 5 and the new tax year started on April 6.
The dates have stayed the same ever since with the 6th April, a date with no real meaning being the start of the UK tax yer.