- Companies
- Civil engineering
- London
- Diamond Core Networks Ltd
Diamond Core Networks Ltd
- Company number
- 15450159
- Incorporated
- 29 Jan 20242 years trading
- Registered office
- 3RD Floor, 86-90, Paul Street, London, England, EC2A 4NE
- Nature of business
- Construction of utility projects for electricity and telecommunications; Construction of other civil engineering projects n.e.c.
Diamond Core Networks Ltd is a 2-year-old private limited company registered in London, company number 15450159, one of 1,853 civil engineering contractors in London. Its next accounts are due at Companies House on 31 October 2026, and the CT600 for the period to 31 January 2026 is due at HMRC on 31 January 2027.
Key dates
Worked out from the year end and filing history on the Companies House register.
Is this your company?
File the accounts to Companies House and the CT600 to HMRC yourself with A.X.E.L Filing. One set of questions, both filings, £49 flat. No accountant, no subscription.
File for Diamond Core Networks LtdOr get a reminder before each deadline
Free. We email you 60, 30, 14, 7 and 1 days before the accounts, CT600 and confirmation statement are due. Unsubscribe in one click.
Financial snapshot, 2025
From the balance sheet at 31 January 2025, as filed at Companies House.
Where Diamond Core Networks Ltd is registered
The registered office is in London (EC2A), in the Hackney local authority area, London. Show EC2A 4NE on a map.
Other trade companies in EC2A
- Simlan Management LtdCleaning companies
- Renova Secure LtdBuilders
- Auraglasspartitions LtdGlaziers
- A2D Professional Cleaning LtdCleaning companies
- Matson Co. LtdProperty developers
- Paint Hub LimitedMechanics and garages
- SJK Construction & Management LtdBuilders
- Cenlora Cleaning Group LtdCleaning companies
Shared registered office
1,581 companies on our pages use this registered office address. An address shared this widely is usually an accountant's office or a company formation agent's service address, not where the business trades from.
What happens if Diamond Core Networks Ltd files late
Companies House charges an automatic penalty the day after the deadline, and it rises the longer the accounts are late. These are the dates for this company's accounts due on 31 October 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Nov 2026 to 30 Nov 2026 | £150 |
| 1 to 3 months late | 1 Dec 2026 to 31 Jan 2027 | £375 |
| 3 to 6 months late | 1 Feb 2027 to 30 Apr 2027 | £750 |
| More than 6 months late | From 1 May 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Feb 2027 | £200 |
| 3 months late | 30 Apr 2027 | another £200 |
| 6 months late | 31 Jul 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Jan 2028 | another 10% of any unpaid tax |
For returns filed on or after 1 April 2026. Late three times in a row and the £200 penalties become £1,000 each.
Company details
As held on the Companies House register.
- Company number
- 15450159
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 29 January 2024 (2 years ago)
- Registered office
- 3RD Floor, 86-90, Paul Street, London, England, EC2A 4NE
- Nature of business
- Construction of utility projects for electricity and telecommunications (SIC 42220)
Construction of other civil engineering projects n.e.c. (SIC 42990) - Year end
- 31 January (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 January 2025
- Last confirmation statement
- 28 January 2026
Filing notes for civil engineering contractors
Civil engineering contractors usually carry plant and machinery, so capital allowances (the annual investment allowance and the main pool) do much of the work in the corporation tax computation.
Similar companies in London
Other active civil engineering contractors registered in London.
- Diamond Cut Construction Ltd2013
- Diamond Deli Ltd2025
- Dideco Limited2017
- Digitaltobe Limited2014
- Dimaraz Construction Ltd2018
- Div Groundwork Ltd2021
- Dko Engineering Ltd2026
- DKRS Services Limited2025
All civil engineering contractors in London · All trades in London · Civil engineering across the UK
Frequently asked questions
When are Diamond Core Networks Ltd's accounts due?
Diamond Core Networks Ltd's next accounts are due at Companies House by 31 October 2026 (in 18 days), covering the period to 31 January 2026.
When is Diamond Core Networks Ltd's CT600 due?
The CT600 for the period to 31 January 2026 is due at HMRC by 31 January 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 November 2026.
Is Diamond Core Networks Ltd still trading?
Diamond Core Networks Ltd is listed as active on the Companies House register as of 1 Oct 2026. Active means it has not been dissolved or entered insolvency; it does not show whether it is currently taking on work.
What does Diamond Core Networks Ltd do?
Diamond Core Networks Ltd is registered under Construction of utility projects for electricity and telecommunications (SIC 42220); Construction of other civil engineering projects n.e.c. (SIC 42990).
How old is Diamond Core Networks Ltd?
Diamond Core Networks Ltd was incorporated on 29 January 2024, 2 years ago.
What is the penalty if Diamond Core Networks Ltd files its accounts late?
Companies House charges £150 if the accounts are up to 1 month late, £375 up to 3 months, £750 up to 6 months and £1,500 after that, doubled if the previous year's accounts were also late. HMRC charges £200 for a CT600 filed a day late and another £200 at 3 months.
Official records
View Diamond Core Networks Ltd on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026). Deadlines are worked out from the register and assume a standard accounting period; a change of year end or a short period moves them. This page is general information, not tax or accountancy advice.