- Companies
- Civil engineering
- London
- One-On Group Limited
One-On Group Limited
- Company number
- 10391882
- Incorporated
- 23 Sep 201610 years trading
- Registered office
- 5TH Floor, 167 - 169 Great Portland Steet, Great Portland Street, London, W1W 5PF
- Nature of business
- Construction of railways and underground railways
One-On Group Limited is a 10-year-old private limited company registered in London, company number 10391882, one of 1,853 civil engineering contractors in London. Its next accounts are due at Companies House on 31 December 2026, and the CT600 for the period to 31 March 2026 is due at HMRC on 31 March 2027.
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 £6,002 (-185%) on the year before, to -£9,247.
- Net assets rose in 2 of 7 year-on-year comparisons on record.
- Current assets of £935 against £10K owed within a year: 0.1 times cover.
- 1 employee on average during the year.
- Balance sheets on record for 8 years, 2017 to 2025.
Net assets by year
| Year end | Net assets | Cash | Current assets | Owed within a year | Employees |
|---|---|---|---|---|---|
| 31 Mar 2025 | -£9,247 | £935 | £10K | 1 | |
| 31 Mar 2024 | -£3,245 | £614 | £3,859 | 1 | |
| 31 Dec 2022 | £14K | £26K | £12K | 2 | |
| 31 Dec 2021 | £8,894 | £14K | £4,644 | 1 | |
| 30 Sep 2020 | £100 | £100 | |||
| 30 Sep 2019 | £100 | £100 | |||
| 30 Sep 2018 | £100 | £100 | |||
| 30 Sep 2017 | £100 | £100 |
Where One-On Group Limited is registered
The registered office is in London (W1W), in the Westminster local authority area, London. Show W1W 5PF on a map.
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What happens if One-On Group Limited 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 December 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Jan 2027 to 31 Jan 2027 | £150 |
| 1 to 3 months late | 1 Feb 2027 to 31 Mar 2027 | £375 |
| 3 to 6 months late | 1 Apr 2027 to 30 Jun 2027 | £750 |
| More than 6 months late | From 1 Jul 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Apr 2027 | £200 |
| 3 months late | 30 Jun 2027 | another £200 |
| 6 months late | 30 Sep 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 31 Mar 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
- 10391882
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 23 September 2016 (10 years ago)
- Registered office
- 5TH Floor, 167 - 169 Great Portland Steet, Great Portland Street, London, W1W 5PF
- Nature of business
- Construction of railways and underground railways (SIC 42120)
- Year end
- 31 March (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 31 March 2025
- Last confirmation statement
- 21 September 2026
- Previous names
- B1ST Support Services Limited (until 11 Oct 2019)
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.
- Onebore Limited2023
- Onergy Limited2019
- Onshore Inspection Ltd2025
- Onyx Engineering Solutions Ltd2026
- Oorabbi Limited2021
- Opk Civils Ltd2026
- Optif Ltd2025
- Optima GS Ltd2019
All civil engineering contractors in London · All trades in London · Civil engineering across the UK
Frequently asked questions
When are One-On Group Limited's accounts due?
One-On Group Limited's next accounts are due at Companies House by 31 December 2026 (in 79 days), covering the period to 31 March 2026.
When is One-On Group Limited's CT600 due?
The CT600 for the period to 31 March 2026 is due at HMRC by 31 March 2027, 12 months after the period end. The corporation tax itself is payable earlier, by 1 January 2027.
Is One-On Group Limited still trading?
One-On Group Limited 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 One-On Group Limited do?
One-On Group Limited is registered under Construction of railways and underground railways (SIC 42120).
How old is One-On Group Limited?
One-On Group Limited was incorporated on 23 September 2016, 10 years ago.
What is the penalty if One-On Group 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 One-On Group Limited 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.