Somewhere in the application form, usually just after the bit where you retyped your entire employment history, there's a little upload box. "Cover letter (optional)."
That word does a lot of damage. Half of you read it as permission to skip. The other half spend two hours writing something the employer never promised to read. Both groups are guessing, and the guess matters more than it used to, because the volume of applications hitting UK employers this autumn has made human attention the scarcest thing in recruitment.
Why "optional" appeared in the first place
Employers didn't add that word out of kindness. They added it because requiring a cover letter suppresses application numbers, and for years the received wisdom was that more applicants meant better hires.
That logic has now collapsed under its own weight. The Institute of Student Employers surveyed 155 member organisations who between them received over 1.8 million applications for roughly 31,000 early careers roles, whilst graduate hiring fell by eight per cent, the weakest year in some time. Do the division. That's roughly 58 applications per vacancy before you account for the ones nobody counts.
Meanwhile the wider market is tightening. ONS figures published on 18 August 2026 show total vacancies down 19,000 on the year, falling in 11 of the 18 industry groups, with the total sitting at 707,000 for May to July, below pre-pandemic levels. Fewer roles, more applicants per role, and the same overworked recruiter reading them at half past four on a Friday.
The honest answer about whether anyone reads it
Some do. Plenty don't. A Salt survey found that 30% of hiring managers said they rarely read cover letters at all, and both hiring managers and candidates rated the CV as the more important document.
That's not an argument for skipping. It's an argument for understanding who reads them and when. In my experience of running shortlists, the cover letter almost never got read at the first pass. It got read at the second, when I had eleven decent CVs, four interview slots and a colleague asking me to justify my choices. That's the moment a cover letter earns its keep.
So the real question isn't "will they read it?" It's "will there be a moment in this process where reading it changes the outcome?"
Situations where you always write one
Some applications are not really optional at all, whatever the form says. Write the letter if:
- You're changing field or sector. Your CV shows what you did; only the letter explains why it transfers. If that's you, pair it with the reasoning in how to prove you can do a job you've never done.
- There's something on your CV that raises an eyebrow. A twelve-month gap, three jobs in two years, a redundancy, a move from Aberdeen to Exeter. Address it in two calm sentences and it stops being a question mark.
- The employer is small. Under about 50 staff, the person reading your application is usually the person you'd report to. They read everything, and they remember tone.
- It's public sector, education, charity or professional services. These fields still run on written evidence against criteria. Skipping the letter here reads as not understanding the culture.
- You have a referral, a genuine connection or specific knowledge of the organisation. None of that fits on a CV.
- You need to flag terms. Part-time hours, a three-month notice period, a start date in January. Better said upfront than discovered at offer stage.
When skipping it is the right call
I'd rather you sent nothing than sent a paragraph of recycled adjectives.
Skip it for high-volume operational hiring where the decision is made on availability and right to work: retail, hospitality, warehousing, most shift-based care roles. Skip it when an agency is the intermediary and has already spoken to you, because your consultant is writing their own summary anyway. And skip it when the form gives you a 200-character box that clearly wasn't designed for prose.
There's one more case. If the only thing you can produce in the time you have is a generic letter, don't. A generic letter is evidence that you apply to everything, which is precisely the impression the reader is already primed to form given that almost half of UK job seekers now use AI somewhere in their applications. The tells are well documented in our piece on using AI to write your cover letter.
The 150-word version nobody teaches you
When a letter is optional, length is the wrong lever to pull. Nobody has ever been rejected for brevity.
Write four short paragraphs and stop. The first says which role and one concrete reason you're applying to this organisation rather than the eleven others advertising the same job. The second gives one piece of hard evidence: a number, a project, an outcome, something with edges. The third connects that evidence to the requirement they clearly care most about, which is almost always the one repeated twice in the advert. The fourth confirms availability and thanks them without grovelling.
That's it. Under 200 words, readable on a phone, no throat-clearing preamble. If you want the longer format for roles that warrant it, the cover letter structure and template covers it properly, and first lines that get you read will keep you away from "I am writing to apply for."
What actually changes the outcome
Here's the part candidates underestimate. The optional cover letter is rarely read in isolation; it's read against the other four shortlisted letters. Yours doesn't have to be brilliant in the abstract. It has to be more specific than the person next to you.
Specificity is cheap to produce and almost impossible to fake. Name the service, the funding round, the new site in Warrington, the regulatory change coming in that clearly created this vacancy. Two sentences of that outperforms 400 words of enthusiasm, because it proves you spent fifteen minutes on their world rather than fifteen seconds on the apply button.
The pragmatic rule I'd use
Decide by the shape of the process, not by how much you fancy writing that evening.
If a named human will read your application before deciding, write the letter. If a system will score it and a recruiter will skim the CV, put your effort into the CV and the application form answers instead. Named contact in the advert, small employer, public sector scoring grid, career pivot: write it. Anonymous portal, high volume, agency-managed, identical to your last twelve applications: don't.
And build yourself a paragraph bank. Six or seven pre-written chunks covering your strongest evidence, your reason for leaving, your availability and your two or three standard skill claims. Then the optional letter costs you twelve minutes rather than two hours and the question of whether to bother mostly answers itself.
Sources
- Vacancies and jobs in the UK: August 2026, Office for National Statistics
- UK labour market statistics, House of Commons Library
- Graduate jobs and recruitment reality, Institute of Student Employers via Wonkhe
- Is a cover letter necessary? Survey results, Salt
- Almost half of UK job seekers now use AI for job applications, Staffing Industry Analysts