Beyond the Red Squiggle: A UK Editor's Guide to Americanisms That Survive Spellcheck

UK spellcheck is a diligent but literal-minded colleague. It knows some American spellings are wrong; it does not know when they are right. In 2026, with automated checks embedded in every writing environment, the risk is less missed typos than misplaced confidence. A clean red-squiggle pass can leave American forms intact because the dictionary accepts them, because the word is also a UK word in another sense, or because the tool has no view on vocabulary at all.

This field guide is for UK copy editors working on authorial prose, business copy and fiction. It covers the usual suspects and the subtler traps, with rules for when to correct, when to leave, and when to query.

Why the Red Squiggle Misses the Point

Spellcheck flags what its dictionary does not recognise. That makes it good at catching color in a UK document and poor at catching program where programme is meant. It also tends to accept both varieties when both are valid somewhere, which is precisely when an editor needs to make a decision rather than outsource one.

The tool is not the problem. The problem is treating a green underline as an editorial judgement. Automated checks are a first pass. They are not a style sheet, and they are not a reader.

The Usual Suspects: Spelling Pairs

program / programme

UK English generally uses programme for a plan, broadcast or schedule. Program is standard in computing. Spellcheck may accept both. Correct to programme in general prose unless the context is software. Leave program in code, product names and quoted material.

license / licence

In UK English, licence is the noun and license is the verb. US English uses license for both. Spellcheck often accepts license in either sense. Correct the noun to licence unless it is a title, brand or quotation.

toward / towards

Both are defensible in UK English, but towards is the more common UK form. Toward is not an error. Query if the author is inconsistent; leave it if it is a deliberate feature of voice.

defense / defence

UK English uses defence. Defense is the US form and is standard in proper names such as the US Department of Defense. Correct in general prose; leave in names and quotations.

practice / practise

In UK English, practice is the noun and practise is the verb. US English uses practice for both. Spellcheck may accept either. Correct the verb to practise unless the author has a stated preference.

cheque / check

UK English uses cheque for a payment and check for verification. US English uses check for both. Correct financial senses to cheque unless the context is American or the term is part of a title.

grey / gray

UK English prefers grey. Gray is the US form and is also a surname. Correct in general prose; leave in names and quotations.

metre / meter

UK English uses metre for the unit and meter for a measuring device. US English uses meter for both. Correct the unit to metre unless the context is American or technical usage has been agreed.

travelled / traveled and cancelled / canceled

UK English generally doubles the final consonant: travelled, cancelled, modelling. US English often does not. Spellcheck may accept both. Apply the house form consistently and record it.

sceptical / skeptical and manoeuvre / maneuver

UK English uses sceptical and manoeuvre. US English uses skeptical and maneuver. These are straightforward corrections in UK prose, but they should be left in quoted titles and direct quotations.

judgement / judgment

UK English uses judgement in general prose and judgment in legal contexts. US English often uses judgment throughout. Apply the house distinction if one exists; otherwise preserve the author's consistent form.

Vocabulary Traps Beyond Spelling

Spellcheck has no view on autumn versus fall, pavement versus sidewalk, lift versus elevator, flat versus apartment, holiday versus vacation, mobile phone versus cell phone, queue versus line, petrol versus gas, rubbish versus trash, or torch versus flashlight. These are not spelling errors. They are register and setting choices.

Other traps are grammatical or idiomatic: gotten, mad meaning angry, quite as an intensifier, Monday through Friday rather than Monday to Friday, and write me rather than write to me. None is automatically wrong. Each needs a decision based on audience, setting and voice.

When to Correct, Leave, or Query

1. Correct in authorial prose when the form is American and the house style is UK, unless the author has made a deliberate choice.
2. Leave in quoted titles, brand names, proper nouns, direct quotations and URLs.
3. Leave in US-set fiction and dialogue when the American form is consistent with setting or character; query if it leaks into narrative voice without apparent purpose.
4. Query where a word is valid in both varieties but changes sense: program, license, check, meter.
5. Record every decision in the style sheet so the next pass does not reopen it.

Keeping Consistency Without Sanding Off Personality

Not every Americanism is an accident. Some authors write transatlantic prose on purpose. Some business voices use US terminology because their market is international. Some fictional narrators are American, or have lived abroad, or are using the vocabulary of a particular profession.

The editor's job is not to normalise every difference into a flat UK default. It is to make the copy consistent with its own intentions. Correct the slips. Leave the choices. Query the ambiguous cases. The test is whether a UK reader would stumble, not whether a dictionary would object.

A Short Fieldwork Routine

Before the main edit, search for the common pairs and note the author's pattern. Read quoted material separately. Check names and brands before changing anything. Keep a running style sheet of decisions. Then read the final text aloud, because the ear catches register shifts that the red squiggle never will.