Why Are Prisoners Called “Lags”?

If you’ve spent any time around British true-crime books, old newspapers, or just earwigged two blokes chatting on a wing, you’ll have heard it: lag, old lag, sometimes just the lags. It sounds dated, a bit sooty round the edges, but it hasn’t disappeared. Where did it come from? Short version: the history is messy, the meanings have shifted, and—like most prison slang—the story is half language, half lived experience.

What “lag” means today (in plain English)

In modern British usage, lag usually means a prisoner, with old lag pointing to an habitual offender—someone who’s been inside more than once and knows how the system breathes. Depending on tone, it can be neutral (“there are a few old lags on that wing”) or a nod of grudging respect (“he’s a proper old lag”). In other mouths it can be dismissive or flatly insulting. Context is doing the heavy lifting.

Quick glossary you’ll actually hear

• Lag: a prisoner.
• Old lag: repeat, experienced prisoner; often someone who “knows the drill”.
• To lag (verb): older slang for “to imprison” or “to inform” in some dialect pockets (see notes below).

Micro-tip

Outside the prison context, “lag” also means delay or “thermal insulation”. Don’t mix your metaphors: nobody’s calling anyone a roll of loft insulation.

Where did “lag” come from? (pick your favourite theory)

Language is rarely tidy, and lag is no exception. There isn’t a single, carved-in-stone origin story. There are a few overlapping ones, and they all make some sense:

1) The transportation thread (18th–19th centuries)

When Britain transported convicts to Australia, lag cropped up in print as a word for a transported prisoner. From there, it stuck to the people rather than the destination. Over time the “transported” bit faded; the “convict/prisoner” bit stayed.

2) The “lag behind” idea

In everyday English, to lag is to fall behind. Some etymologists reckon a lag was someone slow in a forced march to the ship, or simply “the ones left back” from ordinary society. It’s more poetic than provable, but you can hear how the metaphor would land.

3) The verb “to lag” = “to imprison” (Victorian slang)

Victorian dictionaries recorded to lag as thieves’ cant for “to sentence/imprison”. If courts “lagged” you, you became a “lag”. Neat, circular, very slangy—exactly how these things usually spread.

Why we don’t pick just one

All three run in parallel in old sources. Slang isn’t a lab experiment; words win because people use them, not because a committee blessed an origin story.

How the meaning shifted (and stuck)

Originally tied to transportation, lag broadened to mean any prisoner, and then narrowed again in everyday speech to “experienced prisoner”. By the mid-20th century, old lag was everywhere in newspapers and police memoirs. Today, it turns up less in official documents and more in casual speech, memoirs, and drama scripts that want a British, lived-in feel.

Is it rude?

Depends who’s speaking and why. Among prisoners, it can be neutral or even mildly respectful—“he’s an old lag” says “he knows the ropes”, not “he’s a monster”. From officials or media, it can sound lazy or stigmatising. As with most group labels, insiders bend the meaning; outsiders risk flattening it.

Why slang like “lag” survives (even when policy changes)

Prison is its own town with its own clock. Slang grows because people need shortcuts and shared signals. A single word can carry years of context: status, experience, caution, grief, even a joke in the dark. The official language—risk categories, policy frameworks—changes on a minister’s whim. Slang changes slower; it remembers.

What “lag” tells you about the culture

• Experience matters: “old lag” marks seniority without any uniform or badge.
• Economy of speech: one tight word instead of three sentences of backstory.
• Distance from authority: it’s a label that grew from the landings, not from a handbook.

Micro-tip

If you’re writing about prisons, use lag sparingly. A single well-placed “old lag” reads authentic. A paragraph stuffed with “lags” sounds like a parody.

Common confusions & close cousins

English loves homonyms. A few you’ll bump into:

• Lag = informant? In some regional slang, to lag meant to tell on someone. That’s not the dominant modern meaning, but you’ll see it in older sources.
• Lag vs con: American crime writing prefers con or inmate. British usage kept prisoner, con, and lag in different registers.
• Old lag vs lifer: An “old lag” isn’t necessarily serving life; it’s about repeat experience, not sentence length.

How media shaped the word

Newspapers of the 19th and 20th centuries loved crime slang; so do screenwriters. Every time a drama goes for gritty authenticity, words like screw (officer) and lag re-enter the public ear. That keeps the term alive even as official language moves to “people in prison”, “residents”, or other more neutral phrasing.

Language and respect (the grown-up bit)

Words land differently on different ears. If you’re talking to or about someone in custody, listen first, label second. “Prisoner” or “person in prison” is safest; lag is for quoting or context, not for surprising someone with a stereotype they didn’t sign up to.

Why the answer isn’t just etymology

Ask ten old lags how they feel about the word and you’ll get ten answers—pride, weariness, a shrug. The interest isn’t only where the syllables came from; it’s what the word still does: marking experience, drawing lines, defusing tension with black humour, or sometimes turning a person into a type. That last one is why writers should handle it with care.

If you’re researching further

Look at historical dictionaries of cant and slang (Victorian compilers were obsessed with it), newspaper archives around the transportation era, and modern inspection reports to see how official language differs from the landings. The gap between the two is where the culture lives.

Micro-tip

Watch for times when policy language (people on remand, residents) and lived language (lags, cons) collide. That friction is often the whole story.

FAQs: “Lag”, “Old Lag” and the rest

What does “lag” mean in British slang?

Broadly, a prisoner. In everyday use you’ll most often hear it in old lag—a seasoned prisoner who’s been inside before.

Is “lag” offensive?

It can be. Among prisoners it can be neutral or wry; from outsiders it can sound stigmatising. When in doubt, use “prisoner” or “person in prison”.

Where did the word come from?

Likely a mix of (a) transportation-era usage for convicts, (b) the everyday verb “to lag” (fall behind), and (c) Victorian cant where “to lag” meant “to imprison”. No single origin wins outright.

Does anyone still use it?

Yes, though less than in the past. You’ll hear it in prisons, in memoirs, and in British TV/film chasing an older flavour of slang.

Is “old lag” the same as “lifer”?

No. “Old lag” means experienced or repeat prisoner; a “lifer” is about sentence type/length.

What other prison slang might I hear?

Screw (officer), pad (cell), canteen (spend account/weekly shop), nick (prison or segregation), bang-up (locked in cell). Usage varies by region and era.

Bottom line

Lag isn’t just a dusty museum piece. It’s a living word that tells you something about history (transportation), something about culture (experience earns a tag), and something about the power of language to stick long after the policy has moved on. Use it knowingly, not lazily, and you’ll avoid most of the pitfalls.