Filing your self-assessment is rarely the fun part of running a chip shop. Friday night queues, oil that needs changing, a wholesaler who has put the price of cod up again — those are the things that fill your head. But the return matters. Every legitimate expense you claim reduces the profit you are taxed on, and every sloppy claim invites questions you would rather not answer in July.

Here is a plain-English walkthrough of what belongs on the form, what does not, and how to keep the paperwork tidy enough that filing takes an evening rather than a fortnight.

The golden rule: wholly and exclusively for the business

For sole traders and partnerships, HMRC's test is that an expense must be incurred "wholly and exclusively" for the purposes of the trade. Not mostly. Not roughly. That single phrase settles most arguments.

If something serves both you and the shop, split it and claim only the business share. The split does not have to be perfect, but it does have to be reasonable and explainable — 70% business use of a phone line is fine if you can say why. Keep the calculation in your records so you are not reinventing it next January.

If you trade through a limited company, the company's own expenses are not on your personal return at all. You may still file one for salary and dividends, but the principles below apply to the company's accounts rather than your self-assessment.

What you can claim behind the counter

Cost of sales is the biggest number in a chippy, and most of it is straightforward: fish, potatoes, oil, flour and batter ingredients, salt, vinegar, mushy peas, pickles, drinks, ice cream, and the paper, boxes, bags, forks and napkins all of it leaves in.

Then there is the rest of the working week:

• Cleaning chemicals, degreaser, mops and cloths
• Waste oil collection and general trade waste removal
• Card machine fees and delivery platform commissions
• Business insurance, including public liability and contents
• Accountancy fees and trade body subscriptions
• Advertising, menu printing, signage repairs and your website hosting
• Staff wages, employer's National Insurance and pension contributions

One word of caution on stock. If you are holding a freezer full of fish and a store cupboard of oil at the year end, that stock is not an expense yet. Value it, carry it forward, and your accountant will thank you.

Uniforms, laundry and the small stuff

A branded polo or apron with the shop name on it is allowable. So is protective clothing you need for the job — whites, non-slip kitchen shoes, gloves. Ordinary jeans, trainers and coats you would wear on a day off are not, no matter how often they end up smelling of frying.

Washing a uniform that you could not reasonably wear outside work is generally claimable. Keep it modest and consistent.

Vehicles and travel: where owners trip up

There are two sensible routes. The first is actual costs — fuel, insurance, servicing, repairs, MOT, road tax — apportioned by business mileage. The second is HMRC's simplified expenses mileage rates for cars and vans, which replaces all of that with a single per-mile figure. You cannot do both for the same vehicle, and if you use simplified mileage you generally cannot claim capital allowances on the vehicle either.

The bigger trap is knowing which journeys count. Your regular drive from home to the shop is ordinary commuting and is not allowable. Trips from the shop to the cash and carry, the wholesaler, the bank, the post office, or to drop off a delivery are business journeys and are. Keep a log: date, destination, purpose, miles. A notebook in the van does the job.

Big-ticket spending and capital allowances

A new range, a replacement fryer, an extraction system, a walk-in fridge, a van, a full refit — these are capital items, not everyday expenses. You claim them through capital allowances rather than as a normal cost of trading. The Annual Investment Allowance usually lets you deduct the full cost of most qualifying equipment in the year you buy it, subject to a cap, so it is worth checking the current limit before you assume anything.

Cars are treated differently from vans and equipment. If a refit is on the horizon, talk to your accountant before you commit, not after.

What you cannot claim

This is where penalties live, so read it twice.

• Your own drawings. Money you take from the till for yourself is not an expense and does not reduce taxable profit. It is simply your income.
• A wage for yourself as a sole trader. Same reason.
• Personal shopping. Family groceries, clothes, holidays, subscriptions, the personal share of a phone bill.
• Fines and penalties. Parking tickets, speeding fines, late filing penalties — none of it is deductible.
• Entertaining clients or suppliers. Staff entertaining is a different matter, but it has its own rules.
• Loan capital repayments. Interest may be claimable; the capital you repay is not.
• Your own income tax and National Insurance. Paying your tax bill is not a business expense.

Be honest about mixed-use items too. If a van is used for the school run, or the flat above the shop shares your broadband and heating, claim the business proportion — not the whole thing.

Your filing checklist

Before you sit down with the return, work through this:

1. Keep a separate bank account for the business. It is the single change that saves the most time at year end.
2. File receipts, supplier invoices and till rolls by month, not in a carrier bag.
3. Log mileage as it happens, and note the purpose of each trip.
4. Count stock on the last day of your accounting period and value it consistently.
5. Write down your apportionment for shared costs — home, phone, van — and stick to the same method each year.
6. Flag anything unusual for your accountant: a refit, a vehicle purchase, a change of premises, a new delivery contract.
7. Keep records for at least five years after the 31 January filing deadline, longer if you have property income or capital gains in the mix.

The online return is due by 31 January, with payments on account usually falling in January and July. Put a percentage of each week's takings aside for tax as you go, and the deadline stops being a crisis.

One last thing. Tax rules change, and no two chip shops are run the same way — a seaside seasonal site and an inner-city takeaway have very different profiles. A good accountant who understands takeaways will usually save you more than they charge. Treat everything here as general guidance to help you ask the right questions, not as advice on your own return.

Photo: falco / Pixabay