- Companies
- Installers
- London
- Interlocks Security Services Limited
Interlocks Security Services Limited
- Company number
- 16538034
- Incorporated
- 24 Jun 20251 year trading
- Registered office
- 124 City Road, London, EC1V 2NX
- Nature of business
- Other construction installation
Interlocks Security Services Limited is a 1-year-old private limited company registered in London, company number 16538034, one of 2,278 installation companies (insulation, lifts, shutters and similar) in London. Its next accounts are due at Companies House on 31 March 2028, and the CT600 for the period to 30 June 2027 is due at HMRC on 30 June 2028.
Key dates
Worked out from the year end and filing history on the Companies House register.
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Financial snapshot, 2026
From the balance sheet at 30 June 2026, as filed at Companies House.
Where Interlocks Security Services Limited is registered
The registered office is in London (EC1V), in the Islington local authority area, London. Show EC1V 2NX on a map.
Other trade companies in EC1V
- Cardiff Electrical Solutions LtdElectricians
- Edemis Construction LtdBuilders
- Zaylan LtdProperty developers
- Pronto Roofing and Construction LtdRoofers
- Instal Systems LtdPlumbers and heating engineers
- J&R Partners LtdBuilders
- The Tile Craft LtdFinishing trades
- Cathal Od Solutions LtdSpecialist contractors
Shared registered office
1,047 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 Interlocks Security Services 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 March 2028.
| Companies House | Accounts delivered | Penalty |
|---|---|---|
| Up to 1 month late | 1 Apr 2028 to 30 Apr 2028 | £150 |
| 1 to 3 months late | 1 May 2028 to 30 Jun 2028 | £375 |
| 3 to 6 months late | 1 Jul 2028 to 30 Sep 2028 | £750 |
| More than 6 months late | From 1 Oct 2028 | £1,500 |
Penalties double if the accounts were also late the year before.
| HMRC (CT600) | From | Penalty |
|---|---|---|
| 1 day late | 1 Jul 2028 | £200 |
| 3 months late | 30 Sep 2028 | another £200 |
| 6 months late | 30 Dec 2028 | HMRC estimates the tax and adds 10% of the unpaid tax |
| 12 months late | 30 Jun 2029 | 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
- 16538034
- Status
- Active
- Company type
- Private limited company
- Incorporated
- 24 June 2025 (1 year ago)
- Registered office
- 124 City Road, London, EC1V 2NX
- Nature of business
- Other construction installation (SIC 43290)
- Year end
- 30 June (accounting reference date)
- Accounts type
- Micro-entity
- Last accounts made up to
- 30 June 2026
- Last confirmation statement
- 23 June 2026
Filing notes for installation companies (insulation, lifts, shutters and similar)
Installation companies (insulation, lifts, shutters, solar and similar) often buy stock and equipment up front, so stock at the year end and capital allowances both affect the tax bill.
Similar companies in London
Other active installation companies (insulation, lifts, shutters and similar) registered in London.
- Internal Building Design Ltd2008
- Intumex Ltd2026
- Inzonex Ltd2025
- Ips Interface Ltd2020
- Iron Wolf Contractors Ltd2021
- Ironclad Fire Protection Limited2025
- Ironguard Security Systems Ltd2025
- Irwell Fire Ltd2021
All installation companies (insulation, lifts, shutters and similar) in London · All trades in London · Installers across the UK
Frequently asked questions
When are Interlocks Security Services Limited's accounts due?
Interlocks Security Services Limited's next accounts are due at Companies House by 31 March 2028 (in 536 days), covering the period to 30 June 2027.
When is Interlocks Security Services Limited's CT600 due?
The CT600 for the period to 30 June 2027 is due at HMRC by 30 June 2028, 12 months after the period end. The corporation tax itself is payable earlier, by 1 April 2028.
Is Interlocks Security Services Limited still trading?
Interlocks Security Services 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 Interlocks Security Services Limited do?
Interlocks Security Services Limited is registered under Other construction installation (SIC 43290).
How old is Interlocks Security Services Limited?
Interlocks Security Services Limited was incorporated on 24 June 2025, 1 year ago.
What is the penalty if Interlocks Security Services 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 Interlocks Security Services 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.