Self Assessment registration
Tell HMRC after the tax year if you need a return and are not already registered.
BAILEY
UK BUSINESS START-UP HUB · 2026
Start right.
Stay ready.
A practical guide to the decisions, registrations, tax dates and legal duties that turn an idea into a properly run UK business.
Built for founders who want clarity before complexity.
ACCA REGISTEREDEST. 2003BARNSLEY · SOUTH YORKSHIRE
01 — CHOOSE YOUR STRUCTURE
One idea.
Two very different routes.
Start with the commercial reality, then assess tax. These are the usual routes for a one-owner UK business.
STRUCTURE DECISION
Do not choose on tax alone.
Liability, commercial credibility, expected profits, funding, co-owners, administration and exit plans can matter more than headline tax rates.
YOUR FIRST MOVES
- 01Estimate year-one sales, costs, funding needs and personal drawings
- 02Identify contractual, product, property and employee risks
- 03Model both structures with an accountant before signing contracts
WATCH: Incorporating too early creates cost; incorporating too late can expose value and risk.
| Decision point | Sole trader | Limited company |
|---|---|---|
| Legal identity | You are the business | Separate legal person |
| Liability | Generally unlimited | Usually limited, subject to conduct and guarantees |
| Tax base | Income Tax and National Insurance on profit | Corporation Tax; personal tax on value extracted |
| Money out | Drawings do not change taxable profit | Salary, dividends, expenses or director’s loan rules |
| Public filing | No public accounts | Accounts and company information on public record |
| Administration | Lower | Higher, with statutory director duties |
Partnerships, LLPs, charities, CICs and social enterprises need separate advice. Two people trading together should document profit shares, authority, departures and disputes before work starts.
02 — DEADLINES AT A GLANCE
Dates that cost money
when missed.
These are headline timings. Your exact obligations depend on structure, year end, turnover, payroll and circumstances.
Online return and tax
Self Assessment filing, balancing payment and usually the first payment on account.
Corporation Tax payment
Normally measured from the end of the company’s Corporation Tax accounting period.
VAT registration threshold
Monitor taxable turnover on a rolling 12-month basis, not just your year end.
IMPORTANT
Tax payment dates and filing dates are not always the same. A private company normally pays Corporation Tax before its Company Tax Return is due.
03 — YOUR LAUNCH PLAN
From idea to
controlled operation.
A company registration is not a business launch. Work through the commercial, financial and compliance foundations in the right order.
PHASE 01Before commitments
- Define the customer, problem, offer, price and route to market
- Build a realistic cash-flow forecast, including owner living costs
- Decide ownership, authority, profit shares and what happens if someone leaves
- Check name availability, intellectual property, licences and sector regulation
- Review lease, home-working, planning, mortgage or landlord restrictions
PHASE 02Before the first sale
- Form or register the business and complete identity checks
- Open the right bank account and keep personal spending separate
- Set up invoices, bookkeeping, receipt capture and a tax reserve
- Put customer terms, privacy information and credit control in place
- Check VAT, insurance and consumer law before taking money
PHASE 03Before the first employee
- Register as an employer and operate PAYE correctly
- Check the person’s legal right to work in the UK
- Issue employment particulars and comply with minimum wage rules
- Arrange Employers’ Liability cover of at least £5 million
- Assess workplace pension duties from the first day of employment
PHASE 04Every month
- Reconcile the bank, debtors, creditors, payroll and taxes
- Compare actual cash and profit against the forecast
- Move tax money to a separate reserve account
- Review the rolling 12-month VAT position
- Escalate cash pressure early — do not finance losses blindly
04 — TAX & FILING
Know what is due.
Know when it is due.
Filing a return and paying the liability are separate obligations. Your first year can produce unusual periods and overlapping payments.
Self Assessment
- Register
- Usually by 5 October after the end of the tax year if registration is required.
- Tax return
- Paper: 31 October. Online: 31 January following the tax year.
- Pay
- Balancing payment and usually first payment on account: 31 January. Second payment on account: 31 July.
- Taxed on
- Business profit, not drawings. Keep a reserve as profit arises.
- Keep records
- Normally for at least 5 years after the 31 January submission deadline for the relevant tax year.
The £1,000 trading allowance can remove a registration requirement in some cases, but it is gross trading income—not profit—and exceptions apply.
Company compliance
- Start trading
- Tell HMRC within 3 months of becoming active for Corporation Tax.
- First accounts
- Normally 21 months from incorporation for a private company.
- Annual accounts
- Normally 9 months after the financial year end.
- Corporation Tax
- Usually paid 9 months and 1 day after the accounting period ends.
- Company Tax Return
- Normally filed 12 months after the Corporation Tax accounting period ends.
- Confirmation statement
- At least once every 12 months, normally within 14 days after the review period ends.
- Keep records
- Company and accounting records are generally retained for at least 6 years, with longer periods in some cases.
The first accounts period can require two Company Tax Returns because a Corporation Tax accounting period cannot exceed 12 months.
VAT
Registration is compulsory when taxable turnover exceeds £90,000 over a rolling 12-month period, or is expected to exceed it in the next 30 days alone. Voluntary registration can help—or harm—depending on customers, costs and pricing.
Official VAT guidance ↗Making Tax Digital
MTD for Income Tax applies from April 2026 where qualifying self-employment and property income for 2024/25 exceeded £50,000. The thresholds reduce to £30,000 from April 2027 and £20,000 from April 2028.
Check when MTD applies ↗PAYE
Register before the first payday where PAYE is required. Report pay and deductions using payroll software, normally on or before payment. Director-only companies can still require a PAYE scheme.
Register as an employer ↗CIS
Construction contractors must consider registration, subcontractor verification, deductions and monthly CIS returns. A business can be a deemed contractor even if construction is not its main trade.
Construction Industry Scheme ↗LOOKING AHEAD · APRIL 2028
Companies House plans to require accounts to be filed using commercial software in iXBRL format. Build digital records and software discipline now rather than treating bookkeeping as a year-end exercise.
05 — DIRECTOR RESPONSIBILITIES
Limited liability is not
limited responsibility.
You may delegate bookkeeping, payroll and filings. You cannot delegate your legal accountability as a director.
Act within powers
Follow the company’s constitution and use powers for their proper purpose.
Promote success
Act in good faith for the benefit of members while considering wider statutory factors.
Use independent judgement
Take advice, but make and understand the decision yourself.
Exercise care and skill
Apply reasonable care, diligence and the knowledge expected from your role and experience.
Control conflicts
Avoid conflicts, do not accept improper benefits and disclose interests in transactions.
Protect the record
Maintain adequate accounting and company records, file accurately and report changes.
When cash becomes tight
Monitor solvency, creditor pressure, overdue taxes and the basis for continuing to trade. Directors’ priorities can shift towards creditors when insolvency is probable. Take professional advice early; delay destroys options.
NEW REQUIREMENT
Companies House identity verification
Identity verification has been a legal requirement since 18 November 2025. It is compulsory for new directors and PSCs at incorporation or appointment; existing officeholders are brought in through the transition timetable. Keep the personal code secure and check the due date for every role.
Verify or check the rules ↗06 — PEOPLE, RISK & DATA
Protect the downside
before it appears.
Insurance is only one control. Contracts, safe systems, data discipline and correct employment processes matter just as much.
INSURANCE
Compulsory where applicable
- Employers’ Liability: usually required as soon as you become an employer, with at least £5 million cover.
- Motor insurance: vehicles used on the road must have the correct business use and cover.
Commercially important
- Public and product liability
- Professional indemnity
- Cyber and data incident cover
- Property, stock and equipment
- Business interruption and key person cover
A limited company does not remove the need for insurance, and personal guarantees can bypass limited liability.
FIRST EMPLOYEE
Employer checklist
- 01Check the role, employment status and right to work
- 02Register PAYE and choose compliant payroll software
- 03Issue written employment particulars and policies
- 04Comply with minimum wage, holiday and working-time rules
- 05Arrange Employers’ Liability insurance
- 06Assess and complete workplace pension duties
- 07Complete health and safety risk assessments
DATA & CYBER
Personal data creates duties
- Use a lawful basis and tell people how their data will be used
- Collect only what is needed and keep it accurate
- Control access, passwords, backups, devices and suppliers
- Set retention periods and a breach response process
- Check whether the annual ICO data protection fee is due
Most SMEs that pay the ICO fee pay £52 or £78, but exemptions and higher tiers exist. Use the ICO checker rather than guessing.
Check the ICO fee ↗07 — FINANCIAL CONTROL
Profit is an opinion.
Cash is oxygen.
Most start-up failure is not caused by an accounting deadline. It is caused by weak pricing, poor cash conversion, insufficient capital or decisions made from a bank balance rather than useful information.
Price from economics
Include labour, overhead, rework, finance, tax, VAT and a return for risk—not just a competitor’s price.
Forecast cash weekly
Model realistic collection dates, deposits, stock, tax and owner drawings for at least 12 months.
Separate every pound
Business account, tax reserve and personal account. Company money must never become an informal extension of your wallet.
Close the books monthly
Reconcile accounts, review debtors and margins, then act on variances while they can still be fixed.
Fund growth deliberately
More sales can consume cash. Identify the working-capital requirement before accepting volume.
08 — LAUNCH CHECKLIST
Your controlled
start-up checklist.
Tick items as you complete them. Progress is saved on this device only and is not sent to Ashworth Bailey.
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OFFICIAL STARTING POINTS
Go to the source.
Rules and thresholds change. Use this hub to understand the system, then confirm the current position with official guidance and professional advice.
CHARTERED CERTIFIED ACCOUNTANTS · EST. 2003
Accounts and tax
done properly.
Ashworth Bailey helps SMEs, limited companies and owner-managed businesses across Barnsley and South Yorkshire. From first structure decisions to ongoing accounts, tax and advisory support, we give business owners clarity, control and confidence.
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ASHWORTH BAILEY · BUSINESS START-UP & ADVISORY
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