The £375 surprise: how a new company’s first accounts slipped through

The situation

Hollins & Webb is a two-partner practice with around 180 clients. In spring 2025 a long-standing sole trader client, Priya, incorporated her bakery business as Crumb & Crust Ltd on 14 March 2025. The partners set the company up, registered it for Corporation Tax and PAYE, and added it to the practice’s deadline spreadsheet.

The spreadsheet had a column for “Year end” and a column for “Accounts due”, filled in by hand. Someone entered the year end as 31 March 2026 and, out of habit, the accounts deadline as nine months later: 31 December 2026.

What went wrong

Crumb & Crust’s first accounting period ran from 14 March 2025 to 31 March 2026 – just over 12 months. For a first period longer than 12 months, the accounts are due 21 months after incorporation, which is 14 December 2026 – earlier than the date in the spreadsheet.

The work was booked for the last fortnight of December, then pushed into January by the Christmas break. The accounts were filed on 20 January 2027 – more than a month late.

What it cost

• A £375 late filing penalty, the band for accounts between one and three months late. Had they been filed within the first month, it would have been £150.
• An awkward phone call with a client who had only just become a company, and assumed the accountant had it covered.
• A partner’s time drafting an appeal that Companies House was very unlikely to accept.

How Deadlio would have caught it

1. The date comes from Companies House, not a typed column. When the company number was added to Deadlio, the daily check would have read “First accounts made up to 31 March 2026, due by 14 December 2026” straight from the public register.
2. The deadline appears in the right bucket. From mid-November the client would have shown under Due within 30 days, and from 7 December under Due within 7 days on the Overview.
3. The Monday summary email would have listed it four weeks running, to the partner and to the staff member assigned to the client.
4. The Corporation Tax dates follow automatically. Because the first period is longer than 12 months, there are two Corporation Tax periods. Deadlio works the payment and CT600 dates out from the period end, so the team sees them alongside the accounts.

Lessons for any practice

• Never type a first accounts deadline by hand. Take it from the Companies House register.
• Flag every new incorporation for a review of its first period and its Corporation Tax periods.
• Make sure every client has a named person responsible, so a deadline is never “someone’s”.

Related guides

• Annual accounts filing deadline
• Corporation Tax payment deadline
• CT600 return filing deadline
• All deadline guides