- Companies
- Civil engineering
- London
- Onergy Limited
Onergy Limited
- Company number
- 12337739
- Incorporated
- 28 Nov 20196 years trading
- Registered office
- 33 Chelsea Bridge Road, Churchill, London, SW1W 8RG
- Nature of business
- Construction of utility projects for electricity and telecommunications; Engineering related scientific and technical consulting activities
Onergy Limited is a 6-year-old private limited company registered in London, company number 12337739, one of 1,853 civil engineering contractors in London. Companies House shows its accounts as overdue: they were due on 31 August 2026.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Finances
From each year's balance sheet filed at Companies House. Small companies do not have to publish turnover or profit, so these are balance sheet figures.
- Net assets down £519K (-62.2%) on the year before, to £315K.
- Net assets rose in 2 of 4 year-on-year comparisons on record.
- Current assets of £3.2M against £750K owed within a year: 4.3 times cover.
- 28 employees on average, down from 41 the year before.
- Balance sheets on record for 5 years, 2020 to 2024.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 30 Nov 2024 | £315K | £3.2M | £750K | 28 | |
| 30 Nov 2023 | £835K | £5.1M | £537K | 41 | |
| 30 Nov 2022 | £4.1M | £7M | £350K | 35 | |
| 30 Nov 2021 | £418K | £410K | £320K | 35 | |
| 30 Nov 2020 | £13K | £108K | £60K | 24 |
Where Onergy Limited is registered
The registered office is in London (SW1W), in the Westminster local authority area, London. Show SW1W 8RG on a map.
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What happens if Onergy Limited files late
If the accounts reach Companies House today, the late filing penalty is £375 (£750 if last year's accounts were also late). It rises at each step below.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Sep 2026 to 30 Sep 2026 | £150 |
| 1 to 3 months late | 1 Oct 2026 to 30 Nov 2026 | £375 |
| 3 to 6 months late | 1 Dec 2026 to 28 Feb 2027 | £750 |
| More than 6 months late | From 1 Mar 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Dec 2026 | £200 |
| 3 months late | 28 Feb 2027 | another £200 |
| 6 months late | 30 May 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 30 Nov 2027 | 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
- 12337739
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 28 November 2019 (6 years ago)
- Registered office
- 33 Chelsea Bridge Road, Churchill, London, SW1W 8RG
- Nature of business
- Construction of utility projects for electricity and telecommunications (SIC 42220)
Engineering related scientific and technical consulting activities (SIC 71122) - Year end
- 30 November (accounting reference date)
- Accounts type
- Unaudited abridged
- Last accounts made up to
- 30 November 2024
- Last confirmation statement
- 27 November 2024
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.
- Onshore Inspection Ltd2025
- Onyx Engineering Solutions Ltd2026
- Oorabbi Limited2021
- Opk Civils Ltd2026
- Optif Ltd2025
- Optima GS Ltd2019
- Opus Rail Ltd2024
- Oracha Infra Services Ltd2019
All civil engineering contractors in London · All trades in London · Civil engineering across the UK
Frequently asked questions
When are Onergy Limited's accounts due?
Onergy Limited's accounts were due at Companies House on 31 August 2026 and the register shows them as overdue.
When is Onergy Limited's CT600 due?
The CT600 for the period to 30 November 2025 is due at HMRC by 30 November 2026, 12 months after the period end. The corporation tax itself is payable earlier, by 1 September 2026.
Is Onergy Limited still trading?
Onergy Limited is listed as active on the Companies House register (checked 13 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 Onergy Limited do?
Onergy Limited is registered under Construction of utility projects for electricity and telecommunications (SIC 42220); Engineering related scientific and technical consulting activities (SIC 71122).
How old is Onergy Limited?
Onergy Limited was incorporated on 28 November 2019, 6 years ago.
What is the penalty if Onergy Limited 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 Onergy Limited on Companies House for filed documents, officers and the full history.
Based on the Companies House register (snapshot 1 Oct 2026, rechecked 13 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.