IR35 is one of the biggest areas of confusion, risk and financial exposure in the UK tech sector.

And the problem is not limited to contractors anymore.

Today, IR35 affects:

• IT consultancies
• SaaS businesses
• software development agencies
• fintech companies
• AI startups
• recruitment businesses
• contractors
• end clients

At AccounTax Zone, we regularly see tech businesses:

• using contractors without proper IR35 assessments
• relying on generic online tools
• misunderstanding “outside IR35”
• assuming contracts alone provide protection
• facing uncertainty around HMRC risk

The reality is simple: A weak IR35 assessment can create serious tax exposure for both contractors and businesses.

This guide explains:

• what an IR35 assessment actually is
• why it matters in tech businesses
• how HMRC determines employment status
• common mistakes in IT contracting
• and how to reduce IR35 risk properly.

What Is an IR35 Assessment?

An IR35 assessment is the process of determining whether a contractor should be treated as:

• genuinely self-employed (“outside IR35”)
  or
• effectively an employee for tax purposes (“inside IR35”)

In simple terms:

HMRC wants to know:

“If the intermediary company did not exist, would this worker look like an employee?”

If the answer is yes:

• PAYE and National Insurance may apply
• tax liabilities can become significant

This is why IR35 matters so much in the UK tech industry, where contractor usage is extremely common.

Why IR35 Is a Major Issue in the Tech Sector

The IT and tech industry has historically relied heavily on:

• developers
• engineers
• consultants
• project specialists
• cybersecurity professionals
• interim tech experts

Many work through:

• personal service companies (PSCs)
• limited companies
• contractor arrangements

HMRC sees this sector as: high-risk for disguised employment.

As a result: IR35 scrutiny in tech remains high.

Why an IR35 Assessment Matters

A proper IR35 assessment protects:

• businesses
• contractors
• agencies
• finance teams

Without proper assessment: the risk can quietly build for years.

Potential consequences include:

• PAYE liabilities
• employer’s NIC
• interest and penalties
• historic tax exposure
• reputational risk
• contractor disputes

For growing tech businesses, this can become financially damaging very quickly.

Who Is Responsible for IR35 Assessments?

This depends on the type of client.

Small Private Businesses

Where the end client qualifies as “small” under Companies Act rules:

• the contractor usually remains responsible

Medium & Large Businesses

For medium and large businesses:

• responsibility usually shifts to the end client.

The client must:

• assess status
• issue a Status Determination Statement (SDS)
• take reasonable care in the assessment

This is where many tech businesses become exposed.

What HMRC Looks at During an IR35 Assessment

HMRC does not focus on job titles.

They focus on: the reality of the working relationship.

Three major areas are heavily examined.

1. Control

This is one of the biggest IR35 indicators.

HMRC asks:

• Who controls the work?
• Who decides how work is performed?
• Is the contractor operating independently?

Signs pointing toward employment:

• fixed working hours
• direct supervision
• line management control
• mandatory internal processes
• lack of autonomy

Signs supporting outside IR35:

• independent delivery
• project-based engagement
• freedom over methods
• minimal supervision

2. Right of Substitution

Can the contractor send someone else to perform the work?

A genuine substitution clause can support outside IR35 status.

But: fake contractual wording means very little if substitution never exists in practice.

HMRC focuses on:

• whether substitution is realistic
• whether the client would genuinely accept it

3. Mutuality of Obligation (MOO)

This is commonly misunderstood.

HMRC considers:

• Is the business obliged to provide ongoing work?
• Is the contractor obliged to accept it?

Indicators of employment include:

• continuous expectation of work
• rolling engagements
• permanent-style integration

Project-based arrangements with clear deliverables generally carry lower risk.

The Biggest IR35 Mistakes Tech Businesses Make

1. Assuming the Contract Alone Protects Them

Many businesses:

• download template contracts
• insert “outside IR35” wording
• assume they are protected

But HMRC examines: actual working practices.

If reality contradicts the contract: the contract carries limited value.

2. Treating Contractors Like Employees

This is extremely common in tech businesses.

Examples include:

• giving contractors employee-style benefits
• managing them like staff
• requiring fixed office attendance
• integrating them fully into teams
• long-term continuous engagements

This increases IR35 risk significantly.

3. No Formal IR35 Assessment Process

Many growing tech companies:

• have no assessment framework
• rely on assumptions
• never review contractor status

This becomes dangerous during:

• HMRC reviews
• acquisitions
• investment due diligence

4. Blanket Assessments

Some businesses label:

• everyone “inside IR35”
  or
• everyone “outside IR35”

This is risky.

IR35 assessments must consider:

• individual engagements
• actual working arrangements
• level of control
• project structure

Blanket approaches can trigger:

• contractor disputes
• compliance concerns
• reputational damage

5. Ignoring Working Practice Changes

A contractor may begin:

• genuinely outside IR35

…but drift inside over time.

Common examples:

• project becomes ongoing BAU work
• contractor becomes embedded
• control increases
• autonomy decreases

IR35 should be reviewed regularly, not once only.

Why IR35 Creates Financial Risk for Tech Businesses

The liability can be substantial.

Potential exposure includes:

• unpaid PAYE tax
• employer NIC
• apprenticeship levy
• penalties
• interest

And HMRC may review:

• multiple years retrospectively

For fast-growing tech businesses using many contractors: this can become a six-figure issue.

IR35 and Remote Working in Tech Businesses

Remote work does NOT automatically mean outside IR35.

This is another common misconception.

HMRC still examines:

• control
• supervision
• integration
• dependency

A remote contractor can still fall inside IR35 if:

• they work like an employee
• follow fixed structures
• operate under significant control

IR35 Challenges for SaaS & Scaling Tech Companies

Fast-growing businesses often:

• hire contractors rapidly
• prioritise delivery speed
• delay compliance processes

This creates risk areas including:

• undocumented engagements
• unclear project scopes
• inconsistent contracts
• weak assessment evidence

As the business scales: the exposure scales too.

What a Proper IR35 Assessment Should Include

A strong IR35 process should involve:

Contract Review

Reviewing:

• terms
• deliverables
• substitution rights
• control clauses

Working Practice Review

Understanding:

• how the contractor actually operates
• day-to-day realities
• reporting structures

Status Determination

Assessing:

• inside vs outside IR35 risk
• supporting evidence
• risk factors

Documentation

Maintaining:

• assessment records
• SDS documentation
• review processes

This is critical for demonstrating “reasonable care”.

Why Generic IR35 Tools Are Often Not Enough

Many businesses rely entirely on:

• online checkers
• automated tools
• generic templates

But complex tech engagements rarely fit simple boxes.

The challenge:
IR35 depends heavily on:

• nuance
• real-world behaviour
• project structure

A specialist review is often needed.

How IR35 Links to Wider Tech Finance & Tax Planning

IR35 is not just a contractor issue.

It impacts:

• payroll
• employer costs
• cash flow
• workforce planning
• recruitment models
• profitability

This is why specialist Tech Accountants often support:

• contractor strategy
• engagement structuring
• compliance processes
• financial forecasting

How AccounTax Zone Helps Tech Businesses with IR35

At AccounTax Zone, we support:

• IT consultancies
• SaaS businesses
• software agencies
• scaling tech companies

With practical IR35 support.

Our IR35 Support Includes

Contractor Status Reviews

We assess:

• contracts
• working practices
• risk indicators

To provide a clearer IR35 position.

IR35 Assessment Processes

We help businesses:

• implement assessment frameworks
• improve documentation
• reduce compliance gaps

Contractor Engagement Structuring

We advise on:

• engagement models
• operational risk areas
• practical improvements

Ongoing Compliance Support

As your business grows: we help review:

• contractor changes
• evolving risks
• scaling workforce structures

The Goal Is Not Aggressive Positioning. It Is Defensible Positioning.

At AccounTax Zone: we focus on:

• realistic assessments
• evidence-based conclusions
• reducing unnecessary risk

Because: an aggressive “outside IR35” approach without support can become extremely costly later.

Speak to a Specialist Tech Accountant About IR35

If your business:

• uses contractors
• scales through freelance talent
• works with developers or consultants
• is unsure about IR35 exposure

Now is the time to review your position properly.

Book your FREE 30-minute consultation with AccounTax Zone.

We’ll help you review:

• contractor arrangements
• IR35 risks
• compliance gaps
• practical next steps

So you can scale with greater confidence and reduced HMRC risk.

Call: 020 3740 7074
Email: info@accountaxzone.com
Website: accountaxzone.com