- Company number
- 15140575
- Incorporated
- 15 Sep 20233 years trading
- Registered office
- 141 Little Ealing Lane, London, W5 4EJ
- Nature of business
- Construction of domestic buildings
Blackroom Developments Ltd is a 3-year-old private limited company registered in London, company number 15140575, one of 12,075 building contractors in London. Its next accounts are due at Companies House on 30 November 2026, and its first CT600 is due at HMRC on 30 November 2026.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Where Blackroom Developments Ltd is registered
The registered office is in London (W5), in the Ealing local authority area, London. Show W5 4EJ on a map.
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What happens if Blackroom Developments 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 30 November 2026.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Dec 2026 to 31 Dec 2026 | £150 |
| 1 to 3 months late | 1 Jan 2027 to 28 Feb 2027 | £375 |
| 3 to 6 months late | 1 Mar 2027 to 31 May 2027 | £750 |
| More than 6 months late | From 1 Jun 2027 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Mar 2027 | £200 |
| 3 months late | 28 May 2027 | another £200 |
| 6 months late | 28 Aug 2027 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 28 Feb 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
- 15140575
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 15 September 2023 (3 years ago)
- Registered office
- 141 Little Ealing Lane, London, W5 4EJ
- Nature of business
- Construction of domestic buildings (SIC 41202)
- Year end
- 30 November (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 30 November 2024
- Last confirmation statement
- 14 September 2025
- Previous names
- Sma Lofts & Extensions Ltd (until 20 Jan 2025)
Filing notes for building contractors
Building companies often run the Construction Industry Scheme as a contractor, a subcontractor or both. CIS deductions suffered during the year are set against the PAYE bill, and any unrecovered balance at the year end matters when the accounts are drawn up.
Similar companies in London
Other active building contractors registered in London.
- Blackstock G&G Limited2025
- Blackstone Construction Management Ltd2026
- Blackstone Stay Management Ltd2026
- Blackstones Property Ltd2025
- Blackwell Central Construction Ltd2026
- Blackwell Corporation Ltd2017
- Blackwell Cost Consultants Ltd2026
- Blackwolf Property Services Ltd2025
All building contractors in London · All trades in London · Builders across the UK
Frequently asked questions
When are Blackroom Developments Ltd's accounts due?
Blackroom Developments Ltd's next accounts are due at Companies House by 30 November 2026 (in 48 days), covering the period to 28 February 2026.
When is Blackroom Developments Ltd's CT600 due?
The first accounts cover more than 12 months, so there are two Company Tax Returns: one for the 12 months to 30 November 2025, due by 30 November 2026, and one for the period to 28 February 2026, due by 28 February 2027. Corporation tax is payable 9 months and 1 day after the end of each.
Is Blackroom Developments Ltd still trading?
Blackroom Developments Ltd 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 Blackroom Developments Ltd do?
Blackroom Developments Ltd is registered under Construction of domestic buildings (SIC 41202).
How old is Blackroom Developments Ltd?
Blackroom Developments Ltd was incorporated on 15 September 2023, 3 years ago.
What is the penalty if Blackroom Developments 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 Blackroom Developments Ltd 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.