Your guide to rare Machin series stamps

Although billions of Machin stamps were produced, many varieties are surprisingly hard to find. This guide explains what makes the Machin series special, why some Machin stamp varieties are considered rare, and how you can start spotting hidden gems in this vast and historic collection.

What are Machin series stamps?

Machin stamps are named after sculptor Arnold Machin O.B.E., who created the famous bas-relief portrait of Queen Elizabeth II that appears on the stamps.

Key facts:

• First issued: 5 June 1967, replacing the earlier Wilding definitives
• In use until: 4 April 2022
• Design: The Queen’s profile and the value, usually in a single colour
• Scale: An estimated 200 billion printed, with over a thousand known values, colours and formats

The design looks simple at first glance, but the series contains a huge range of variations. Paper types, phosphor bands, perforations, printers, security features, and barcodes all create opportunities for scarce and valuable Machin stamps.

What makes a Machin stamp “rare”?

Rarity in the Machin series usually comes from a mix of factors rather than age alone. Here are the main reasons certain issues are harder to find.

1. Short print runs and specialist uses

Some Machin issues were printed in small numbers or used only in limited settings. Examples include:

• The tall engraved high-value Machins of the late 1970s and early 1980s, and the smaller engraved high values of 1999
• Specialist formats like Horizon labels and certain Post & Go Machin stamps, issued only through specific machines

These rarely appear in general mixtures, making them sought after by collectors.

2. Trials, transitional issues and barcodes

Modern Machins also offer unexpected rarities.
A good example is the 2021 trial 2nd class Machin with a 2D data-matrix barcode, produced mainly for business use.

Barcoded Machins released in 2022 were the last of the series before the switch to King Charles III. Some of these values may become future rarities, as they were withdrawn quickly before older stamps lost postal validity on 31 January 2023.

Suggested article: The Penny Black Lives On

Key areas to explore for rare Machin stamps

Many collectors focus on specific parts of the series where valuable Machin stamps are more likely to appear.

Early pre-decimal and decimal issues

The first Machins appeared in pre-decimal currency in 1967, with high-value pre-decimal issues following in 1969. Decimal Machins began in 1970, especially around Decimal Day in 1971.

What to look for:

• Type differences in the same value (e.g., spacing variations)
• Shade differences and paper types
• Phosphor band positions that create scarcer varieties

High values and special commemorative definitives

High-value definitives and commemorative Machin-based designs can be rewarding areas to collect:

• Tall portrait £1, £2 and £5 high values from 1977 onwards
• The 1990 Penny Black 150th anniversary Machins, which include Queen Victoria’s head in the background
• The Millennium Machin of 2000, issued for a limited period

Some of these appeared only in specific booklets or miniature sheets.

Royal Mail are celebrating these definitives this year by releasing a special collection of eight of Queen Victoria's stamps. Including the favourite Penny Black 

How to spot a potentially rare Machin

When sorting through a batch of definitives, ask yourself:

• Is the format unusual? Horizon labels, Post & Go, booklet panes and coils are always worth checking.
• Do the codes look unusual? Examine the iridescent overprint for incorrect or missing letters.
• Does the shade look off? Short-lived values often had only one standard shade, so anything different might be worth investigating.
• Is it on cover? Commercially used examples of certain high values or early barcoded trials can be significantly scarcer than mint stamps.

A good catalogue or specialist Machin resource is essential for confirming whether your find is genuinely rare or simply a normal variety.

Building your rare Machin collection

Because the Machin series is so extensive, it helps to start with a clear focus. You might choose:

• A specific period (pre-decimal, early decimal, Security Machins)
• A format (booklets, coils, Post & Go, barcoded issues)
• A theme (high values, anniversary issues, Machin stamp varieties)

Keep notes on shades, codes and printings. A magnifying glass and UV lamp are useful tools for identifying varieties and phosphor bands. As you gain experience, you’ll start to spot patterns and recognise valuable Machin stamps more quickly.

Above all, enjoy the hunt. The Machin series is one of the most fascinating definitive collections in the world. Hidden among the everyday 1st class golds are varieties and rarities that can turn any kiloware session into a true collecting adventure.

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