£73k
+527%vs Sept 2024Active03482926Private limited companyWelwyn Garden City
MERCURY SECURITY SYSTEMS LTD
From public filings as at 31 Aug 2026; may contain errors or be out of date. Verify at Companies House · Terms
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What does Mercury Security Systems Ltd sell?
Registered activity: Manufacture of doors and windows of metal (SIC 25120). We’re building product and service lists for UK companies. Get this one when it’s ready.
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01
Summary
MERCURY SECURITY SYSTEMS LTD is an active private limited company (company number 03482926) incorporated on 18 December 1997, registered in Welwyn Garden City. Its registered activity is manufacture of doors and windows of metal (SIC 25120). Latest small accounts cover the period ending 30 September 2025, showing net assets of £73k and cash of £40k, with 30 employees on average. Net assets rose 527% on the prior period (£12k).
Peer position · net assets
By net assets it sits in the upper half of 1,042 comparable companies in the UK (median £8,316, upper quartile £95k).
02
Ownership and control
No active person with significant control is registered.
- Mr Michael Rothwell
- has significant influence or control
Persons with significant control hold 25% or more of shares or voting rights. Smaller shareholdings are only listed in confirmation-statement documents. Directors and secretaries: see the officers list at Companies House.
03
Key dates
- Incorporated
- 18 December 199728 yrs ago
- Next accounts due
- 30 June 2027in 250 days
- Confirmation statement due
- 1 January 2027in 70 days
Due dates are expected from Companies House filing rules; confirm on the official register before relying on them.
04
Activity
- SIC 25120
- Manufacture of doors and windows of metal
- SIC 43210
- Electrical installation
- SIC 80200
- Security systems service activities
- SIC 84250
- Fire service activities
- Accounts type
- Total Exemption Full
- Size band
- MicroCompanies Act thresholds
05
Financials
£40k
−13%vs Sept 2024Not reported
30
−17%vs Sept 2024| Period end | Net assets | Cash | Debtors | Creditors <1y | Turnover | Profit | Employees |
|---|---|---|---|---|---|---|---|
| 30 September 2025 | £73k | £40k | £1.16m | — | — | — | 30 |
| 30 September 2024 | £12k | £46k | £1.25m | — | — | — | 36 |
Cash per employee£1,344Cash ÷ average employees
Figures as filed in iXBRL accounts at Companies House. "—" means the line was not reported in that filing.
06
Filing and accounts signals
- Net assets above zeroNet assets £72,521 at 30 September 2025
- Net assets up 10% or more on the prior period+527.1% vs prior period
- Incorporated five or more years agoIncorporated 18 December 1997
Neutral facts read from the register and filed accounts, each with its evidence. They are not a rating, a prediction or advice, and may be incomplete or out of date. How each signal is derived.
07
Timeline
- Next accounts duein 250 days
- Confirmation statement duein 70 days
- Accounts period endNet assets £73k · small accounts
- Accounts period endNet assets £12k · small accounts
- Incorporated
08
Similar companies in Hertfordshire
- ESAVIAN LIMITEDBiggleswade · inc. Feb 1989
- MERCURY FIRE LIMITEDWelwyn Garden City · inc. Jan 2009
- JEWERS DOORS LIMITEDBiggleswade · inc. Jul 1984
- RYTERNA UK LIMITEDSt. Albans · inc. Mar 2012
- INTELLIGENT MEMBRANES LIMITEDCroydon · inc. May 2013
- 5EC ALU LTDStevenage · inc. Jun 2018
All companies incorporated on 18 December 1997 · in Dec 1997.
09
Reminders for MERCURY SECURITY SYSTEMS LTD
Get an email before each filing deadline — accounts and confirmation statement — so nothing is late.