CT600 preparation, marginal relief, R&D credits, and the post-April 2023 regime — delivered by qualified UK tax professionals.
The Corporation Tax landscape changed fundamentally on 1 April 2023. After over a decade at a flat 19% rate, the UK reintroduced a two-tier structure: a 19% small profits rate for companies with augmented profits up to £50,000, a main rate of 25% for profits exceeding £250,000, and marginal relief for those in between. This wasn't a minor tweak — it changed how every CT600 is calculated and requires your team to understand concepts like the marginal relief fraction (3/200) that many practitioners haven't encountered since the pre-2015 regime.
Add to that the associated companies rules under CTA 2010 s.25A (which replaced the old associated companies provisions and now include 51% subsidiaries within the count), the merged R&D expenditure credit scheme that replaced the separate SME and RDEC regimes from April 2024, and ongoing changes to capital allowances — including the permanent full expensing regime for main rate plant and machinery announced at Autumn Statement 2023 — and it's clear that Corporation Tax preparation demands a level of technical knowledge that goes far beyond simply filling in boxes on a CT600.
The CT600 is the backbone of Corporation Tax compliance, yet it's surprisingly common for practices to file returns with errors in the computational sections. Our training walks your team through every section of the CT600 and its supplementary pages — from the basic company information and turnover figures through to the detailed tax computation, capital allowances claims, and the all-important box 63 (tax chargeable after marginal relief). We cover the interaction between CT600 and iXBRL accounts tagging, the correct treatment of prior period adjustments, and the common errors HMRC's systems flag for enquiry.
The marginal relief calculation is straightforward in isolation — ((Upper Limit – Augmented Profits) × Augmented Profits / Taxable Total Profits) × 3/200 — but becomes complex when you introduce associated companies, short accounting periods, and the interaction with dividend income. Our training covers the definition of “associated company” under the new s.25A rules (which importantly include dormant companies and 51% subsidiaries that were previously excluded), how to apportion the upper and lower limits, and the treatment of non-UK resident associates. We use worked examples with multiple associated companies, staggered year-ends, and companies entering or leaving the associated group mid-period.
The R&D landscape has been substantially reformed. From 1 April 2024, the SME R&D scheme and the RDEC scheme merged into a single above-the-line merged scheme with a notional tax credit of 20% of qualifying expenditure (or 27% for R&D-intensive SMEs). Our training covers the qualifying conditions under the BIS guidelines, what constitutes qualifying expenditure (including the new rules on overseas subcontractor costs), the additional information form that HMRC now requires with every claim, and the common pitfalls that trigger HMRC compliance checks. We also address the transitional rules for companies with accounting periods straddling 1 April 2024.
Corporation Tax loss relief is a powerful planning tool but one that many practice staff apply mechanically without understanding the options available. Our training covers current-year relief under CTA 2010 s.37, carry-back claims (including the extended 3-year carry-back that was available for losses incurred in 2020–2022), carry-forward against total profits under s.45A (which the 2017 reforms introduced with the 50% restriction above £5 million), terminal loss relief under s.39, and group relief under Part 5. We examine the interaction between loss relief and the small profits rate — particularly the counter-intuitive scenarios where claiming less relief can sometimes produce a better after-tax result due to marginal relief dynamics.
Capital allowances remain one of the most valuable areas of Corporation Tax planning, and the landscape has shifted significantly. The permanent full expensing regime (100% first-year allowance for main rate plant and machinery expenditure by companies) was confirmed at Autumn Statement 2023, alongside the 50% first-year allowance for special rate assets. Our training covers the qualifying criteria for full expensing (including the exclusion of certain leased assets and second-hand equipment), the ongoing Annual Investment Allowance (£1 million), the structures and buildings allowance (3% straight-line), and the mechanics of writing-down allowances at 18% (main pool) and 6% (special rate pool). We also address the interaction between capital allowances and the Corporation Tax computation — particularly the impact of large allowances claims on the marginal relief calculation.
We review your client portfolio to understand the types of CT computations your team handles — micro-entities, SMEs, groups, R&D claimants, companies with overseas operations. This ensures training is directly relevant to your day-to-day work.
Each team member completes a short technical assessment covering the current CT regime. We identify individual knowledge gaps so we can pitch the training at the right level and focus on areas that need the most attention.
We deliver focused sessions on each topic area — marginal relief, R&D, capital allowances, loss relief — using worked examples drawn from scenarios your team actually encounters. Sessions are interactive with Q&A throughout.
Participants work through practical exercises — computing CT liabilities with associated companies, preparing R&D claims, calculating marginal relief — under guidance. This is where the learning becomes embedded and applicable.
Every participant receives comprehensive reference materials including legislation summaries, rate tables, worked examples, and decision trees for common Corporation Tax scenarios. Plus 30 days of email support for technical questions.
Your team will understand the marginal relief calculation, associated companies rules, and loss relief options inside out — eliminating the errors that trigger HMRC enquiries and damage client confidence.
A team that fully understands R&D credits, full expensing, and loss relief options can proactively identify tax planning opportunities that save your clients thousands — strengthening relationships and fee justification.
With the CT landscape changing annually, our training ensures your team is current on the latest Finance Act provisions, HMRC guidance, and case law — not working from outdated knowledge.
When juniors and semi-seniors prepare CT computations correctly the first time, managers and partners spend less time on review and corrections — freeing capacity for higher-value advisory work.