This month we celebrate 50 years since Britain ‘went decimal’. We explore the impact on society and how our stamps changed at the time.

Decimal Day or ‘D Day’ as it was referred to, fell on 15 February 1971 in Great Britain and on 14 February in Northern Ireland. This hotly anticipated event meant each country, in changing its currency, witnessed a social and economic shift unlike all others before. 

The change meant a system of currency (pounds, shillings and pence) in use for hundreds of years became history overnight. Prior to the transition, there were 12 pennies to the shilling and 20 shillings to the pound – this meant there were 240 pence in each pound.

The old system was far from straightforward, especially for young children, as it was based on multiples of 12. This meant school children were drilled on the 12 times tables from a very young age. The change to a new modern currency where the pound was subdivided into 100 new pence eradicated the shilling altogether.

Pre-decimal Coins

The pre-decimal system had been standardised throughout much of Europe for almost a thousand years, with decimalisation introduced to most countries during the 18th and 19th centuries. The UK had experimented with decimalisation in 1849 by introducing the florin (a two-shilling coin or one tenth of a pound) but went no further. The ‘outdated’ currency system remained in place well into the 20th century, outlasting almost all other countries.

The decision to change over to a decimal system was made in parliament in 1966, giving plenty of time to plan a smooth transition in theory. However, people had to learn a completely new form of spending as millions of cash machines, vending machines, phone boxes, parking metres and supermarket tills had to be converted to accept the new coins and banknotes.

Image of a cover of a pamphlet. Blue text across the top reads ‘Postal Decimalisation’ followed by red text reading ‘Bulletin no. 1’. Below the text are images of the follow coins: new penny (reverse), new 5 pence (reverse), new 50 pence (reverse), new 50 pence (face), new 10 pence (reverse), new 2p (reverse), new half penny (reverse) and the face of an unidentified coin

Postal Decimal Bulletin no 1 cover (POST 63/78)

The Decimalisation of GB Stamps

The change had a big impact on stamps and the postal service. Stamp collectors saw a shift to the age-old customs of their hobby. In many ways it was a new era for stamp collecting.

The last GB pre-decimal commemorative stamps issued

It was not just stamp collectors and philatelists who had to adapt of course, as simply using the postal service following decimalisation meant having to learn a completely new set of values. Due to the confusion, when attempting to post a letter, a common question asked at many Post Office counters was “how much is that in old money?”

Stamp designs had to change to accommodate the new decimal system. These new designs were rolled out in three stages over a twenty-month period in order to ease the new system in.

17 June 1970 – Britain’s first decimal stamps

High Value large Machin stamps were issued. They were valued closely (in shilling terms) to the pre-decimal high values. The equivalent stamp values were: 2s 6d/10p, 5s/20p & 10s/50p.

Pre-decimal High Value Machin 2’6

Pre-decimal High Value Machin 5′

Pre-decimal High Value Machin 10′

Post Office poster with new Decimal High Values

First Day Cover, 17 June 1970

15 February 1971 – D Day

Full sets of low value Machin decimal stamps were issued, ranging from ½p to 9p. Pre-decimal stamps were still valid (including those issued after King George V) and could be used simultaneously with the new value stamps.

Approved colour scheme for decimal stamps

Issued low value pre-decimal definitives

Issued low value decimal definitives

The main problem faced on D day – other than the general confusion of the new system – was that the first national strike in the history of the Post Office was happening. It took place between 20 January and 7 March 1971 meaning most of the country’s postal services ground to a complete halt. Interestingly, when postal services resumed the cost of first-class postage was 3p (or 7.2d). Prior to the strike it was 5d.  

Due to the strike, stamp enthusiasts still received a postmarked first day cover for 15 February, but with an added cachet referring to the delay due to the postal strike. 

First Day Cover during postal strike

29 February 1972 – The last day pre-decimal stamps were valid

From this day forth only stamps bearing a decimal value were valid for postage meaning all pre-decimals were officially demonetised. £1 stamps remained valid, and the £1 Machin changed its value typeface, but all other values from the pre-decimal era were taken out of service. The change-over was complete. 

Last day of validity cover

Challenges for the Post Office

When on 1 March 1966 the Commission of Inquiry on Decimal Currency recommended Britain introduce a decimal currency, followed by the passing of Decimal Currency Act in May 1969, the next two years were spent preparing for the change.

Poster with black background. White text reads ‘Decimal Currency in the Post Office. Below that red text reads ‘Get a leaflet here’. There is a blue 3p definitive stamp, and the a 1p coin on top of a 2p coin.

Poster advertising decimal currency (POST 110/398)

This was an immense challenge for the Post Office as set out in the first Postal Decimalisation Bulletin:

‘The conversion to decimal currency on 15th February 1971 will be a gigantic operation for the Post Office. With around 25 000 public counters to convert to decimal working, a payroll of more than 400 000, and 250 000 coin-operated machines, the task is immense, but by no means insurmountable.’


Despite the significant challenges involved, the Post Office saw the introduction of decimal currency as a positive step:

‘Decimal currency will also, in itself, be an important aid to productivity; it has the considerable advantage that money is treated like ordinary numbers and, as a result, money calculations will become quicker, easier, and less prone to error.’


To ensure a successful transition staff needed to be trained to handle the new currency.

Decimal currency training cover in pink

Decimal currency training cover (POST63/73)

For the first 18 months, old coins could be used to pay for goods, but change was only given in decimal currency. This meant that staff needed to not only understand the new currency but be able to quickly determine the required change. This would be the equivalent of accepting payment in Euros and having to give change in pounds sterling. Training manuals we produced for counter staff including questions such as:

  1. List the 6 new decimal coins which will be in use on D day
  2. Say how many new pence=£1
  3. Which £sd coins will still be in circulation
  4. Customer wants 25p postal order and two 3 1/2p stamps and only has 1d,3d, and 6d coins. A) how much in old coins did you ask for? b) how much change did you give?

The training also included questions on how to write different amounts for accounting purposes and how to refer to the new amounts.

Poster showing eight rows of small ovals with a line going through the middle of the ovals. Each oval has a letter in it, forming the words ‘even when/ decimal/ National/ Savings/ Bank/ gives you/ a good/ interest

Artwork for a poster ‘Even when decimal the National Savings Bank gives you good interest’ (POST 109/907)

Today there are only two countries in the world which use non-decimal currencies (Mauritania and Madagascar). It seems that decimal pounds and pence are here to stay.

– The Postal Museum’s Collections Team

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