The Short Answer
There are three ways to get AI work done in a UK business, and the right one depends far less on the technology than on how long you will need the work.
Employ someone when AI is going to be a permanent, growing part of what you do, when you have enough work to keep a specialist busy for years, and when you have somebody senior who can judge whether their work is any good. Bring in a contractor when you need a specific skill for a defined stretch and you can supervise the outcome yourself. Use an agency when you have a problem rather than a vacancy, when you need it working in weeks rather than months, and when you would rather buy a delivered result than manage a person.
Most UK small and medium businesses looking to add a chatbot, a voice agent or an automation are in the third position and think they are in the first. This guide is about telling the difference, and about the things that changed in 2026 that make the choice harder than it was.
What Actually Changed in 2026
Three shifts have moved the maths on employment, and none of them are about AI.
Employer National Insurance costs more. HMRC's rates and thresholds for employers guidance on gov.uk confirms the secondary Class 1 rate is 15%, up from 13.8%, charged on earnings above a secondary threshold that was cut in April 2025 and is held at that lower level until April 2028. The Employment Allowance offsets some of this for eligible employers. The practical effect is that the gap between somebody's salary and what they actually cost you has widened, and it widened most for smaller employers taking on their first specialist hires.
Pension duties are unchanged but easy to forget. Automatic enrolment still applies from the first qualifying employee, with the earnings trigger and qualifying earnings band held for 2026/27 according to the Department for Work and Pensions review published on gov.uk. Employer contributions are a real cost on top of salary, not an optional extra, and The Pensions Regulator publishes the current thresholds.
Dismissal risk is being rewritten. The Employment Rights Act 2025 has been phasing in through 2026. Acas and gov.uk's implementation timeline record day-one rights to statutory sick pay and paternity leave delivered in April 2026, the Employment Tribunal claim time limit rising to six months from October 2026, and unfair dismissal protection changing from 1 January 2027 with a shorter qualifying period and the removal of the cap on the compensatory award. Confirm the current position with an employment solicitor before you rely on any of this, because the timetable has moved before.
None of that makes hiring wrong. It does mean that hiring a specialist you are not certain you need, into a role you cannot yet describe precisely, is a more expensive experiment in 2026 than it was in 2023.
The Comparison
| Employ someone | Contractor | Agency | |
|---|---|---|---|
| Best when | AI is permanent and central to the business | A defined skill gap for a defined stretch | You have a problem, not a vacancy |
| Time to first working thing | Months, including notice periods | Weeks, once you find the right one | Weeks, from an agreed scope |
| Who carries delivery risk | You | You | The agency, under a written scope |
| Breadth of skill | One person's depth | One person's depth | A team's range across the stack |
| What happens when they leave | You lose everything they knew | Contract ends, knowledge leaves | Handover is contractual |
| Ongoing commitment | Salary, on-costs, pension, tribunal risk | Day rate for the term | Fixed scope, then a support arrangement |
| Compliance burden | PAYE, auto-enrolment, employment law | Off-payroll status determination if you are medium or large | Supplier contract and a DPA |
| Worth it when | The work never stops | The work is well specified | The work has an end |
The Contractor Trap Nobody Mentions
Contractors look like the flexible middle option, and for a small business they often are. But the off-payroll working rules change the picture the moment you stop being small.
HMRC's off-payroll working guidance on gov.uk, last updated in February 2026, puts the responsibility for determining a contractor's employment status on the client where the client is a medium or large private-sector organisation, or any public-sector body. If that is you, you must take reasonable care over the determination, issue the contractor a Status Determination Statement setting out your decision and the reasons for it, keep records of every determination and the fees paid, and run a process for handling disagreements. HMRC's Check Employment Status for Tax tool exists to help, but using it does not remove the obligation to take reasonable care.
Where the client is small and outside the public sector, the contractor's own intermediary decides. So the same contractor is a light-touch arrangement for a ten-person firm and an administrative commitment with a tax liability attached for a larger one. Businesses that grow across that boundary are the ones caught out, because nothing about the contractor changes — only the rules that apply to you.
An agency engagement sits outside all of this. You are buying a delivered outcome from a supplier under a contract for services, not engaging a person whose employment status you have to assess.
What You Are Actually Buying in Each Case
The honest framing is not cost. It is what you get for the commitment.
With an employee you buy availability and accumulation. They are there every day, they learn your business, and after a year they know things nobody wrote down. That is genuinely valuable, and it is why serious AI programmes end up with in-house people. The catch is that one person has one set of skills. An AI chatbot that needs a language model, a CRM integration, a front end, some infrastructure and a clinical or regulatory sanity check is four disciplines. Very few individuals cover all four well, and the ones who do are not applying for jobs at small firms.
With a contractor you buy a specific skill on a clock. That works when you already know exactly what needs building and can tell whether it has been built properly. It works badly when you cannot, because a contractor is paid for time rather than outcome, and the person best placed to notice a problem is the person being paid while it persists.
With an agency you buy a delivered result and somebody else's risk. A fixed scope means the estimate is the supplier's problem rather than yours. A team means the four disciplines above are covered without four hires. The trade-off is real: an agency will never know your business the way an employee does, and you should be suspicious of one that claims otherwise after a discovery call.
How to Tell Which One You Are
Work through these honestly.
Can you write the job description? If you cannot describe the role in a paragraph without using the phrase "and other AI stuff", you do not have a vacancy yet. You have a problem you have not scoped.
Is there two years of work? Count the actual projects, not the ambitions. If the honest answer is one chatbot and some automation, that is a project, and projects do not need employees.
Who judges the work? If nobody in the business can tell good AI engineering from bad, hiring puts you in the position of paying a salary to someone whose output you cannot evaluate. An agency at least gives you a fixed scope to measure against, and a contract you can end.
What happens if they leave in month four? With an employee or a contractor, the knowledge walks. Ask any supplier how handover works, in writing, before you sign anything — and ask the same question of yourself before you hire.
Are you medium or large? If so, the contractor route brings the status determination duties above. Factor in the administration, not just the day rate.
What We Do, and When We Say Don't
BigBerri is a Manchester AI development company working with businesses across the UK. We build AI chatbots, voice agents, automation and integrations, and every project is quoted as a fixed price after a free discovery call, never a day rate — which means an over-run is our problem rather than yours. The code and the accounts are set up in your name and are yours on completion, so ending the relationship does not end the thing we built.
We also tell people not to hire us. If your need is one simple link between two mainstream apps, a builder tool on your own account will do it and we will say so. If AI is genuinely going to be central to your business for years, and you have the volume of work and the seniority to supervise it, hire — and we would rather you heard that on a free call than after signing something.
The most common sensible pattern we see is a hybrid: an agency builds the first working system and proves the value, then the business hires around a role it can finally describe precisely, because it now has something concrete to point at. Scoping the problem first and hiring second is almost always cheaper than the reverse.
For how we scope and quote engagements, see /services. For sector detail, /industries sets out the systems and constraints we work with in each. If you are weighing this up for a specific project, related reading is at /blog/ai-automation-agency-cost-uk on what an agency fee actually buys, and /blog/ai-development-cost-uk-2025 on what drives the size of an AI project.
Next Step
If you are not sure whether you have a vacancy or a project, that is exactly what a discovery call is for. Book a free one at /contact, message us on WhatsApp, or call, and we will tell you honestly which of the three routes fits — including when the answer is that you should hire rather than use us.
Frequently Asked Questions
Is it cheaper to hire an AI developer or use an agency?
That depends entirely on how long the work lasts, and the salary is only part of the comparison. Employing someone adds employer National Insurance at the secondary Class 1 rate, automatic enrolment pension contributions, recruitment, equipment and the management time to supervise them, and it commits you to all of that whether or not there is work that month. An agency engagement is scoped and ends. As a rule of thumb, permanent and growing work favours hiring; a defined problem favours an agency.
Can one AI developer build everything we need?
Rarely. A production chatbot or voice agent usually needs language model work, an integration into your CRM or booking system, a front end, some infrastructure, and someone who understands the rules your sector works under. Those are four or five disciplines. Individuals who genuinely cover all of them exist but are scarce and expensive, so a single hire often becomes a single point of failure rather than a team.
What are the off-payroll working rules and do they apply to us?
HMRC's off-payroll working guidance on gov.uk puts responsibility for deciding a contractor's employment status on the client, where the client is a medium or large private-sector organisation or any public-sector body. If that applies, you must take reasonable care, issue a Status Determination Statement with your reasons, keep records of determinations and fees, and have a process for disagreements. Small private-sector clients are outside it and the contractor's intermediary decides instead. Confirm your own size status before engaging anyone.
What happens to our system if we stop working with an agency?
It should keep running, and you should ask any supplier this before signing because the answer is not universal. We build on accounts set up in your name rather than ours, and the code and those accounts are yours on completion and full payment. Handover is part of the engagement rather than a favour at the end of it.
Should we hire first and then build, or build first and then hire?
Build first, in most cases. Hiring before you have scoped the problem means writing a job description for work you cannot yet describe, and interviewing candidates against a standard nobody in the business can apply. Getting a first system working gives you a concrete thing to hire around, a much sharper role definition, and evidence about whether the work is really permanent.