Crossroads Well, Oklahoma, USA Update

19 June 2026

This announcement contains inside information for the purposes of Article 7 of the Market Abuse Regulation (EU) 596/2014 as it forms part of UK domestic law by virtue of the European Union (Withdrawal) Act 2018 ("MAR"), and is disclosed in accordance with the Company's obligations under Article 17 of MAR.

Union Jack Oil plc

("Union Jack" or the "Company")

Crossroads Well, Garvin County, Oklahoma, USA Update

Union Jack Oil plc (AIM: UJO), a UK and USA focused onshore hydrocarbon, production, development, exploration and investment company announces that, further to the Company's announcement on 15 May 2026, the Company is providing an update on the Crossroads well, Garvin County, Oklahoma USA. Union Jack holds a 43% interest in this well.

The Crossroads well encountered good hydrocarbon shows at several levels from the Hoxbar down to the Basal McLish intervals. Four intervals with production potential were perforated and tested.

Following testing the well has been deemed non-commercial and will be plugged and abandoned in due course.

For further information, please contact:

Union Jack Oil plc [email protected]

David Bramhill

SP Angel Corporate Finance LLP +44 (0)20 3470 0470

Nominated Adviser and Joint Broker

Matthew Johnson

Richard Hail

Jen Clarke

Zeus Capital Limited +44 (0)20 3829 5000

Joint Broker

Antonio Bossi

Simon Johnson

George Duxberry

Gneiss Energy Limited + 44 (0)20 3983 9263

Financial Adviser

Jon Fitzpatrick

Harbour Access +1 (475) 477 9402

USA Investor Relations

Jonathan Paterson