Lansdowne Celtic Sea Limited (“Lansdowne, LCSL, or the Company”), was founded as an upstream oil and gas entity, focused on exploration and appraisal opportunities offshore Ireland. Lansdowne targeted shallow water (less than 100 metres) areas of the Irish shelf as these provided lower cost drilling opportunities, which combined with the favourable fiscal terms, had the potential to deliver high value oil and gas reserves.

The Company recorded a loss on ordinary activities before tax for the year of £ nil (2024:£15,883,639 ).

The Company’s balance sheet as at 31 December 2025 is on page 6 and shows net liabilities of £ 21,760,713 (2024:£21,760,713 ). As at 31 December 2025, the Company held £nil (2024: £nil) in intangible assets incurred in connection with the Company’s exploration licences in the Celtic Sea and their associated work programs.

LCSL continues to hold a 9% interest in the Helvick Lease Undertaking containing the Helvick Jurassic oil discovery. An extension to the term of this remains under consideration at the Department of Climate, Energy and the Environment.

By way of background, Lansdowne’s major activity offshore Ireland related to the Barryroe oil and gas field, where it held a 20% interest and participated in the successful 48/24-10z well, which flowed at a rate of 3,514 bopd and 2.93 mmscfd, demonstrating the commercial potential.

An application for a Lease Undertaking was submitted in April 2021, as a follow-on authorisation to Lansdowne’s Exploration Licence SEL1/11, in which it held a 20% interest. Under the terms of the SEL1/11 Licence the licencees had the right to progress to a Lease Undertaking.

After considerable delay, in May 2023 the application for a Lease Undertaking was refused by the Irish Department of the Environment, Climate and Communications.

Following this, in June 2023 Lansdowne gave Ireland notice that that a dispute existed under the Energy Charter Treaty (“ECT”).

On 22 December 2025, the Company announced that it had signed an Engagement Letter (“EL”) with Diamond McCarthy LLP to pursue its ECT arbitration claim against Ireland for the refusal to award a Lease Undertaking for the Barryroe Oil and Gas field.

The EL provides sufficient funds, on a non-recourse basis, to cover legal fees and costs associated with pursuing the claim through to resolution. Diamond McCarthy is a U.S. law firm with decades of experience in cross-border litigation and international arbitration. To date, Lansdowne has been advised on its claim by Mantle Law, a London and United Arab Emirates based international arbitration law firm with a focus on energy, construction, and infrastructure disputes. Mantle Law and Diamond McCarthy will co-counsel to progress the claim to conclusion.

The gross compensation claim is expected to be in excess of $100 million plus accrued interest and any related penalties. In the event of a successful award in an amount of approximately $100 million, Lansdowne’s share of the proceeds, based on the funding agreements with Diamond McCarthy and Mantle Law, is expected to be between 60% and 70%.

Following the achievement of third-party litigation funding the next steps of the arbitration process have commenced with the filing of the Request For Arbitration (“RFA”) at the International Centre for the Settlement of Investment Disputes (“ICSID”) in Washington DC and confirmation of the entry of this onto the register in early May 2026.

The next step in the process is the appointment of a tribunal and the Company’s lawyers have commenced discussion with Ireland to achieve this.

During the year the company decided to write down the value of the intangible asset due to the uncertain nature of the underlying circumstances.

The principal risk facing the Group is the potential failure to secure compensation through legal proceedings for its investment in the Barryroe oil and gas project.

The value of compensation being sought is linked to the pricing of both oil and gas.

The Brent Oil Price averaged around c.$70/bbl in 2025, but following the outbreak of hostilities in early 2026, the price has risen to more than $100/bbl, where it lies today and future contracts remain above $80/bbl through to early 2027.

The Irish gas price is linked to the UK gas price as the majority of Ireland’s gas supply flows through the interconnector from the UK. UK prices rose rapidly as a result of the war in Ukraine and in 2024 averaged above 100p/therm. Prices have risen sharply since hostilities began in the Middle East with supply of LNG from Qatar greatly reduced. The UK NBP price is currently above 120p/therm and forward prices remain above 100p/therm for the rest of 2026.

Previous Independent Competent Persons Reports have demonstrated that the Barryroe project delivers robust returns at an oil price of c.$70/bbl and a gas price of p/therm. The current much higher product prices, fully support Lansdowne’s claim for compensation.

As a participant in the upstream oil & gas industry, the Group is exposed to a wide range of risks in the conduct of its operations.

Following the loss of the Barryroe Asset, the Group work has concentrated on seeking compensation through the Energy Charter Treaty.

The Company is exposed to a wide range of risks in the conduct of its operations. The Directors are responsible for the effectiveness of the Company’s risk management activities and internal control purposes. These risk include:

Financial risks:

•     Ability to raise finance to pursue litigation

•    Cost inflation

•    Oil and gas price movements

•    Adverse taxation legislative changes

•    Third party counterparty credit risk

•    Adverse foreign exchange movements

•    Changes in government policy

Operational risks:

•    Loss of key employees

•    Delay and cost overrun on projects, including weather related delay

•    HSE incidents

•    Poor reservoir performance

•    Exploration and appraisal well failures

Strategic and external risks:

•    Failure of third-party services

•    Deterioration of capital markets, inhibiting efficient equity and/​or debt raising for developments

•    Commercial misalignment with co-venturers

•    Material fall in oil or gas prices

Market Risks:

The key risk facing the Company is failure to be granted compensation for the loss of the Barryroe asset, which is being pursued under the Energy Charter Treaty.

On behalf of the board

For the financial year ended 31 December 2025 the company was entitled to exemption from audit under section 477 of the Companies Act 2006 relating to small companies.

The members have not required the company to obtain an audit of its financial statements for the year in question in accordance with section 476.

The directors acknowledge their responsibilities for complying with the requirements of the Companies Act 2006 with respect to accounting records and the preparation of financial statements.

These financial statements have been prepared and delivered in accordance with the provisions applicable to companies subject to the small companies regime.

The directors of the company have elected not to include a copy of the income statement within the financial statements.

Lansdowne Celtic Sea Limited is a private company limited by shares incorporated in England and Wales. The registered office is C/O Pinsent Masons LLP, 30 Crown Place, London, EC2A 4ES. The company's principal activities and nature of its operations are disclosed in the directors' report.

The financial statements have been prepared in accordance with Financial Reporting Standard 101 Reduced Disclosure Framework (FRS 101) and in accordance with applicable accounting standards.

The financial statements are prepared in sterling, which is the functional currency of the company. Monetary amounts in these financial statements are rounded to the nearest £'000.

The financial statements have been prepared under the historical cost convention. The principal accounting policies adopted are set out below.

As permitted by FRS 101, the company has taken advantage of the following disclosure exemptions from the requirements of IFRS:

• inclusion of an explicit and unreserved statement of compliance with IFRS;

• presentation of a statement of cash flows and related notes;

• disclosure of the objectives, policies and processes for managing capital;

• disclosure of key management personnel compensation;

• disclosure of the categories of financial instrument and the nature and extent of risks arising on these financial instruments;

• the effect of financial instruments on the statement of comprehensive income;

• comparative period reconciliations for the number of shares outstanding and the carrying amounts of property, plant and equipment, intangible assets, investment property and biological assets;

• disclosure of the future impact of new International Financial Reporting Standards in issue but not yet effective at the reporting date;

• a reconciliation of the number and weighted average exercise prices of share options, how the fair value of share-based payments was determined and their effect on profit or loss and the financial position;

• comparative narrative information;

• related party disclosures for transactions with the parent or wholly owned members of the group.

Where required, equivalent disclosures are given in the group accounts of Lansdowne Oil & Gas plc. The group accounts of Lansdowne Oil & Gas Pls are available to the public and can be obtained as set out in note 7.

The Directors have prepared the financial statements on the going concern basis which assumes that the Company will continue in operational existence for at least 12 months from the date of the approval of these financial statements. The Company shows net current liabilities of £21,760,713 (2024: £21,760,713 ) and net liability of £ 21,760,713 (2024: £21,760,713 ), and is subject to the principal risks and uncertainties described in the Directors’ report. The Company is dependent on funding provided by its parent entity, Lansdowne Oil & Gas Plc (“Lansdowne”), which has confirmed that amounts due to it will not be called for a period of at twelve months from the date of approval of the Company’s financial statements and that it will continue to provide financial support to the Company to meet its liabilities as they fall due.

The Directors have carefully reviewed the future prospects of the Company and its future cash flows, having assessed this the Directors have a reasonable expectation that the Company has adequate resources to continue in operational existence for the foreseeable future, being at least the next 12 months from the signing of these financial statements.

For this reason, the directors continue to adopt the going concern basis for the preparation of the Financial Statements. Accordingly, these financial statements do not include any adjustments to the carrying amount or classification of assets and liabilities that would result if the company was unable to continue as a going concern.

The Company’s intangible assets comprised exploration and evaluation assets with a carrying value of £Nil (2024: Nil).

Cash and cash equivalents include cash in hand, deposits held at call with banks, other short-term liquid investments with original maturities of three months or less, and bank overdrafts. Bank overdrafts are shown within borrowings in current liabilities.

The company recognises financial debt when the company becomes a party to the contractual provisions of the instruments. Financial liabilities are classified as either 'financial liabilities at fair value through profit or loss' or 'other financial liabilities'.

Equity instruments issued by the company are recorded at the proceeds received, net of direct issue costs. Dividends payable on equity instruments are recognised as liabilities once they are no longer at the discretion of the company.

The costs of short-term employee benefits are recognised as a liability and an expense, unless those costs are required to be recognised as part of the cost of inventories or non-current assets.

The cost of any unused holiday entitlement is recognised in the period in which the employee’s services are received.

Termination benefits are recognised immediately as an expense when the company is demonstrably committed to terminate the employment of an employee or to provide termination benefits.

The average monthly number of persons (including directors) employed by the company during the year was:

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The company's ultimate parent undertaking is Lansdowne Oil & Gas plc, a company incorporated in England and Wales.

Copies of the Lansdowne Oil & Gas plc consolidated financial statements are available on the company’s website at www.lansdowneoilandgas.com