Santus Intelligentia Accountants
At SIA, we are a firm of professional accountants delivering practical and tailored tax and payroll services designed to fuel business growth — whether you’re launching a new venture or managing a growing portfolio.
We work with
About Santus Intelligentia Accountants (SIA)
Discover how our team’s insight and experience can help shape the financial future of your business.
Accounting & Bookkeeping
Keep your finances in check with real-time bookkeeping, management reports, and end-of-year accounts.
Payroll & Auto Enrolment
Hassle-free payroll processing, RTI submissions, and workplace pension compliance.
Business Formation & Start-up Advice
From company registration to building a solid business plan — we’ll help you start strong.
Tax Strategy & Compliance
Minimise liabilities and stay fully compliant with personal and business tax guidance.
Cloud Accounting
Access your finances anytime, anywhere with cloud-based systems and expert support.
Specialist Advice
Non-resident landlords, IR35 compliance, SPVs for property — we’ve got you covered.
Accounting & Bookkeeping
Stay compliant and in control with accurate financial records, management accounts, and end-of-year reporting. We support SMEs with outsourced, cloud-enabled bookkeeping services that scale as you grow.
Payroll & Auto Enrolment
Our efficient payroll solutions ensure staff are paid on time and in line with HMRC regulations. We also manage RTI submissions, workplace pensions, and compliance for peace of mind.
Business Start-up & Growth
From company formation to investor-ready business plans, we help new ventures launch with clarity and confidence — and provide ongoing support as you scale.
Tax Strategy & Compliance
We reduce tax liabilities through smart planning, covering corporation tax, R&D tax credits, personal tax, and support with HMRC investigations.
Practical, tailored accounting and tax for entrepreneurs, start-ups, SMEs, contractors and landlords — from the 37th floor of One Canada Square, for clients right across the UK.
We understand the needs of small and growing businesses — our services are tailored to match your stage of growth.
From tax planning and payroll to business formation and growth strategy, everything you need under one roof.
No hidden fees. We offer fair, fixed-cost packages with flexible support to suit your budget.
Work smarter with real-time cloud accounting platforms, supported by our responsive team.
You’ll work with qualified professionals who keep your business compliant and your finances secure.
We’re not just number crunchers — we’re your financial partner, helping you plan, grow and succeed.
For financial years beginning on or after 6 April 2025, individual companies and LLPs must meet at least two of the following limits to qualify for a size category.
Exceeds any two of the medium-sized thresholds.
A company normally must meet or breach the thresholds for two consecutive financial years before its size classification officially changes.
Illustrative estimates for 2026/27. Salary assumes England, Wales or Northern Ireland, no pension or student loan. Corporation Tax assumes a 12-month period with no associated companies or exempt distributions.
Tax code 1257L · England, Wales & NI · no pension or student loan
12-month period, no associated companies · marginal relief applied
19% up to £50k · 25% over £250k · marginal relief in between
Registration threshold: £90,000 rolling 12-month taxable turnover
Santus Intelligentia Accountants (SIA) is built on a commitment to reliable, transparent and forward-thinking accountancy services. We support individuals, start-ups and SMEs with everything from company formation and bookkeeping to tax strategy and growth advisory.
Our team combines traditional values with a tech-enabled approach — giving you the insight and control you need to run your business with confidence. Whether you're just starting out or scaling rapidly, we're here to simplify your financial journey and unlock long-term value.
We're professional accountants based in Canary Wharf, giving SMEs and entrepreneurs practical, tailored accounting and tax support — so the paperwork is handled and you can focus on growing your business.
fSIA on Facebook
Choose a service to see how we help. Got a specific question? Our AI assistant can answer it instantly.
We apply every available tax relief and allowance tailored to your business, to minimise your tax liabilities and maximise your profits. Above all, we support the growth of your business.
We understand the needs of small and growing businesses — our services are tailored to your stage of growth.
From tax planning and payroll to formation and growth strategy — everything under one roof.
No hidden fees. Fair, fixed-cost packages with flexible support to suit your budget.
Real-time cloud accounting platforms, supported by our responsive team.
Qualified professionals who keep your business compliant and your finances secure.
Not just number crunchers — your financial partner, helping you plan, grow and succeed.
200+ official forms and online services, organised and searchable. Find the right form in seconds.
From a start-up mission in 2014 to a Canary Wharf practice serving clients UK-wide — every step has been about giving clients more of what they need.
Clear, affordable accountancy for new businesses and entrepreneurs navigating complex financial systems.
Dedicated tax planning for individuals and businesses, helping clients reduce liabilities and grow confidently.
Fully managed payroll for growing teams, including RTI submissions and pension compliance.
A cloud-first model keeping clients' data accessible, secure and compliant through the pandemic.
Specialist support for non-resident landlords, international investors and buy-to-let SPV structuring.
A 24/7 AI tax assistant for instant answers — with our team one click away.
Explore our calculators or contact SIA for help with Income Tax, VAT, Corporation Tax, payroll, landlords and deadlines. Live AI replies require the supplied PHP backend to be configured on your hosting.
We offer fair, fixed-fee packages with no hidden fees. Your fee depends on your business type, transactions and whether you need VAT or payroll — we'll give you an exact quote after a free consultation.
Yes, any time. We handle professional clearance with your previous accountant, HMRC authorisation and software set-up, so the handover is seamless.
You're very welcome at One Canada Square, but most clients work with us by phone, video and our cloud platforms — wherever they are in the UK.
It depends on your profit level, risk and plans. Since dividend tax rose and the dividend allowance fell to £500, incorporation suits fewer people than it used to — we'll model both options for you.
From 6 April 2026, sole traders and landlords with combined qualifying income over £50,000 must keep digital records and send quarterly updates to HMRC. The threshold falls to £30,000 in 2027 and £20,000 in 2028.
Don't ignore it and don't reply in detail before taking advice. Contact us and an accountant will review it and, if needed, deal with HMRC on your behalf.
We set up, migrate and support your accounts, payroll and tax on the leading platforms — so your numbers are always live, accurate and MTD-ready.
Tell us a little about you and we'll be in touch within one working day.
37th Floor, 1 Canada Square, London E14 5AA
