Corporation Tax · Central London
Corporation tax returns in Marylebone High Street
If your Marylebone High Street company has bought equipment, vehicles or software this year, made a loss, or has profits between £50,000 and £250,000, the Corporation Tax computation is where money is won or lost. We get the allowances, reliefs and marginal rate right, then file the return online for a fixed fee, serving all of Central London remotely.
from £199 · fixed, per return
Next deadlines
- Company tax return (CT600) due 12 months after your year end (a 31 December year end files by 31 December)
- R&D claim deadline: 2 years after the end of the accounting period (and the pre-notification window of 6 months after the period for first-time claimants)
- Companies House accounts due 9 months after your year end (a 31 December year end files by 30 September)
- Corporation Tax payment, 9 months and 1 day after your year end (a 31 December year end pays by 1 October)
Who this is for
Corporation Tax for Marylebone High Street
Limited companies in Marylebone High Street of every size below the large-company regime: companies whose accounts are prepared by another firm or in-house and need the tax return filed, companies with capital expenditure to claim, companies that have made a loss and want it used well, groups of associated companies, and companies whose CT600 is already overdue.
What is included
Everything inside the fixed fee
- Corporation Tax computation reconciling accounting profit to taxable profit, with every adjustment explained
- Capital allowances claimed in full: annual investment allowance, full expensing, writing-down allowances and the special rate pool
- Loss relief planned and claimed: carry back, carry forward and group relief where it applies
- Marginal relief and associated-company rules applied correctly between the 19% and 25% rates
- CT600 with supplementary pages, iXBRL-tagged accounts and computation, filed electronically with HMRC
- Payment note with amount, due date and HMRC reference, and reminders before the payment and filing dates
How it works
Corporation Tax from Marylebone High Street, step by step
Tell us your situation
A short message or call about what you do and what needs filing. We ask the questions that determine the right package and nothing more.
Fixed fee in writing
You receive one price for the work, confirmed by email before anything starts. It does not change if the job takes longer than we expected.
Send records, review the draft
Records come by WhatsApp or email. We prepare the draft, explain the figures in plain English and answer your questions.
We file, you get the receipts
Once you approve and the fee is settled, we submit electronically and forward the HMRC or Companies House acknowledgement the same day.
Why IGI
Why Marylebone High Street businesses file with IGI
No hourly rate and no surprise invoice. Marylebone High Street clients know the fee for corporation tax before they send a single document, and it stays fixed.
We work to the HMRC and Companies House calendar, not an appointment diary. Clients in Marylebone High Street get reminders at 60, 30 and 7 days before each date that applies to corporation tax.
We serve Marylebone High Street remotely by design: records by WhatsApp or email, drafts back for approval, filing electronic. The saving on premises is passed to you in the fee for corporation tax.
A named person handles your corporation tax from Marylebone High Street and knows the file, so you are not re-explaining your business to a different helpdesk each time.
We explain corporation tax in the words Marylebone High Street business owners use, not in accountant's shorthand, and we show our working so you can check it.
Nothing is filed for Marylebone High Street until you have reviewed and approved it. You see the draft, you ask questions, you sign off, then we submit and send you the receipt.
Local facts
About Marylebone High Street
Marylebone High Street is in Central London, within Westminster, in the W1G postcode district, England. Income tax in England follows the UK rates: 20% basic to £50,270, 40% higher to £125,140 and 45% additional, with the personal allowance of £12,570 tapered away above £100,000. National Insurance, VAT and Corporation Tax are UK-wide, and Stamp Duty Land Tax applies to property purchases.
| Place | Distance | Direction |
|---|---|---|
| Marylebone, Westminster | 0.1 mi | W |
| Baker Street, Westminster | 0.4 mi | NW |
| West End of London | 0.4 mi | SW |
| Bryanston and Dorset Square | 0.5 mi | W |
| Oxford Circus | 0.5 mi | SE |
| Fitzrovia | 0.6 mi | NE |
| Marble Arch | 0.6 mi | SW |
| Mayfair | 0.6 mi | S |
Worth knowing
Rules that come up in this work
Switching accountants
You can switch accountant at any point in the year. The new firm requests clearance and your records from the old one, which cannot withhold your own documents though it may hold its own working papers until its fees are settled. Agent authorisations with HMRC and Companies House are transferred, and the next deadline is picked up without a gap.
Closing a company
Striking off a company is cheap but must be done in order: stop trading, file the final accounts and CT600, pay the tax, close VAT and PAYE, distribute the remaining assets, close the bank account, then apply. Anything left in the company at dissolution passes to the Crown. Distributions up to £25,000 are taxed as capital gains; above that a formal liquidation is usually needed to keep capital treatment.
Employer National Insurance
Since April 2025 employer National Insurance has been 15% on earnings above a £5,000 secondary threshold, a substantial increase for small employers. The Employment Allowance rose to £10,500 at the same time to soften it for the smallest businesses. Directors deciding their own salary weigh this cost against the Corporation Tax deduction a salary provides.
Workplace pensions and auto-enrolment
Workplace pension compliance is part of payroll, not separate from it. Each pay period the payroll assesses who is eligible, calculates employer and employee contributions on qualifying earnings between the lower and upper thresholds, and sends the contribution file to the scheme. The minimum total is 8%, and many employers choose to contribute more as a recruitment advantage.
Dormant companies
A dormant company is one with no significant accounting transactions in the year, where the only permitted entries are the payment for shares on incorporation, Companies House fees and penalties. It still files a confirmation statement and simplified dormant accounts every year. A bank charge or an accountant's fee paid from the company ends dormancy and requires full accounts.
The trading and property allowances
Not every small income needs a tax return. The trading allowance exempts the first £1,000 of self-employment or casual income and the property allowance does the same for rental income, each measured on gross receipts. They cannot be combined with rent-a-room relief on the same income, and claiming the allowance means giving up the expense deduction for that source.
Crypto records and reporting
Crypto tax splits into capital gains on disposals and income on rewards, with different rates and different reporting. The £3,000 annual exempt amount and the 18% and 24% rates apply to gains; staking, mining and airdrop income is taxed at marginal income tax rates. HMRC's nudge letters to holders have increased sharply, and a voluntary disclosure before one arrives is treated far more leniently.
Questions
Corporation Tax questions from Marylebone High Street
Can you deal with HMRC if they open an enquiry into the return?
Yes. As your authorised agent we receive and respond to HMRC correspondence. Routine queries about a return we filed are handled at no extra charge. A formal enquiry is handled through our HMRC investigation service at fixed fees per stage, so you know the cost before deciding how to proceed.
Does R&D affect my Corporation Tax return?
Yes. Research and development relief is claimed on the CT600 and reduces the tax or generates a credit. Since the merged scheme, first-time claimants must notify HMRC within six months of the period end. Our R&D service prepares the technical report and the computation; the claim then goes on the return we file.
What is iXBRL and do I need to worry about it?
HMRC requires the accounts and computation attached to a CT600 to be tagged in iXBRL, a machine-readable format. We produce and validate the tagged files as part of the service. If another firm prepared your accounts we tag their figures; you never deal with it directly.
My CT600 is overdue. What now?
The £279 rescue fee gets it prepared and filed quickly from your accounts. The £100 late penalty is fixed, rising to £200 after three months and then to tax-geared penalties at six and twelve months, so speed matters. If there is a reasonable excuse we draft the appeal as part of the fee.
When is Corporation Tax paid and the return filed?
Tax is due nine months and one day after the end of the accounting period; the CT600 is due twelve months after it. Companies with profits over £1.5 million pay by instalments instead. Interest runs on late payment from the due date, and a late return attracts a £100 penalty rising to 10% of the tax at twelve months.
What are capital allowances and what can I claim?
Capital allowances are the tax equivalent of depreciation. The annual investment allowance gives 100% relief on up to £1 million of qualifying plant and machinery a year; full expensing gives 100% on new main-rate assets without limit; cars and integral features go into pools at 18% or 6%. The £299 package reviews every asset purchase in the year.
Do you have an office in Marylebone High Street?
No. IGI Accounting is an online-only firm. We serve Marylebone High Street and every other UK postcode remotely, with records sent by WhatsApp or email and everything filed electronically. The absence of local premises is why the fee for corporation tax is the same in Marylebone High Street as anywhere else in the country, and why there is nothing to visit and nothing to print.
Is corporation tax in Marylebone High Street really the same price as elsewhere?
Yes. The fee published on this page is what a client in Marylebone High Street pays and what a client in any other part of England pays. It is confirmed in writing before work starts and the invoice matches the quote. Where a higher package applies because your situation is more complex, we say so at the quote stage, never afterwards.
Let us take the deadlines off your plate in Marylebone High Street
Tell us what you need. You get one fixed fee in writing, and nothing is filed until you approve it.