Tax Diary: June to July 2025 Deadlines That May Still Matter

This tax diary highlights key UK tax deadlines that fall between June and July 2025. It is relevant for taxpayers reviewing whether all obligations from this mid–tax-year period were dealt with correctly.

July is a significant month in the tax calendar. Even where deadlines have passed, unresolved payments or filings from this period can still result in penalties, interest, or HMRC follow-up action.

Key Tax and Payroll Deadlines for June and July 2025

• 1 June 2025 – Due date for corporation tax due for the year ended 31 August 2024.
• 19 June 2025 – PAYE and NIC deductions due for month ended 5 June 2025. (If you pay your tax electronically the due date is 22 June 2025).
• 19 June 2025 – Filing deadline for the CIS300 monthly return for the month ended 5 June 2025.
• 19 June 2025 – CIS tax deducted for the month ended 5 June 2025 is payable by today.
• 1 July 2025 – Due date for corporation tax due for the year ended 30 September 2024.
• 6 July 2025 – Complete and submit forms P11D return of benefits and expenses and P11D(b) return of Class 1A NICs.
• 19 July 2025 – Pay Class 1A NICs (by the 22 July 2025 if paid electronically).
• 19 July 2025 – PAYE and NIC deductions due for month ended 5 July 2025. (If you pay your tax electronically the due date is 22 July 2025).
• 19 July 2025 – Filing deadline for the CIS300 monthly return for the month ended 5 July 2025.
• 19 July 2025 – CIS tax deducted for the month ended 5 July 2025 is payable by today.
• 31 July 2025 – Pay second self-assessment payment on account for 2024-25.

Why June and July Deadlines Still Matter

Tax obligations do not fall away once a deadline has passed. Where a return was not filed or a payment was not made on time, HMRC continues to treat the liability as outstanding until it is resolved.

The 31 July Self Assessment payment date is particularly important, as interest and penalties may apply if amounts remained unpaid after this point, an issue often identified later during a review by a tax specialist in London.

Common Obligations Around June and July

Deadlines during this period often relate to:

• Self Assessment payments on account due by 31 July
• Balancing payments, where applicable
• VAT return submissions and payments
• PAYE and National Insurance reporting and payments

Which obligations applied will depend on your circumstances, such as whether you were self-employed, a landlord, an employer, or otherwise within Self Assessment.

What Happens If a Deadline Was Missed?

If a tax deadline in June or July 2025 was missed, HMRC may have charged interest from the original due date. Penalties can also apply in some cases.

The longer an issue remains unresolved, the greater the potential cost. Even where no immediate penalty notice was issued, HMRC may still pursue the matter later, sometimes following intervention from a tax advisor in London or as part of wider compliance checks.

Why It Is Worth Reviewing Now

Some taxpayers assume that once the July deadline has passed, nothing further can be done. In practice, addressing missed obligations sooner can limit further charges and reduce compliance risk.

Reviewing whether all June–July 2025 obligations were met can help avoid unexpected demands or enforcement action later in the year.

HMRC Guidance on Late Tax Payments

HMRC explains how interest and penalties apply to late tax payments on
GOV.UK.

Did You Miss Any June or July 2025 Deadlines?

Whether any action is required now will depend on which obligations applied to you at the time and whether they were dealt with correctly. For individuals and businesses in Farringdon and nearby areas such as Clerkenwell and Barbican, CIGMA Accounting can review your position and confirm whether anything remains outstanding or needs to be addressed.