Mereo BioPharma Group plc

Disclosure Controls and Procedures

Our management, with the participation of our principal executive officer and principal financial officer, has evaluated the effectiveness of our disclosure controls and procedures (as such term is defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act and regulations promulgated thereunder) as of December 31, 2023, or the Evaluation Date. Based on such evaluation, our principal executive officer and principal financial officer have concluded that, as of the Evaluation Date, our disclosure controls and procedures were effective in recording, processing, summarizing and reporting, on a timely basis, information required to be included in periodic filings under the Exchange Act and that such information is accumulated and communicated to management, including our principal executive officer and principal financial officer, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

Management’s Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Rule 13a-15(f) under the Exchange Act. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with policies or procedures may deteriorate. Our internal control over financial reporting is a process designed under the supervision of our principal executive officer and principal financial officer to provide reasonable assurance regarding the reliability of financial reporting and the preparation of our financial statements for external reporting purposes in accordance with accounting principles generally accepted in the United States of America.

Our management conducted an assessment of the effectiveness of our internal control over financial reporting based on the criteria set forth in “Internal Control - Integrated Framework (2013)” issued by the Committee of Sponsoring Organizations of the Treadway Commission.

Based on this assessment, our management concluded that, as of December 31, 2023, our internal control over financial reporting was effective.

Remediation of Previously Reported Material Weaknesses

In connection with the preparation of our unaudited interim condensed consolidated financial statements as of and for the six-month period ended June 30, 2023, a material weakness in our internal control over financial reporting was identified. This related to a control deficiency which impacted the presentation of significant or non-routine transactions in the unaudited condensed consolidated statement of comprehensive loss in accordance with IFRS prior to us having to comply with the domestic reporting regime under the Exchange Act.

This control is designed to ensure that, significant or non-routine transactions are identified and that an appropriate accounting analysis is performed by sufficiently qualified individuals and reviewed by appropriate members of management to validate the conclusions, including any judgments and/or estimates.

Management concluded that the control was appropriately designed, however in respect of a transaction involving the income statement classification of a single item, the control did not operate effectively. Management has since taken steps to remediate this deficiency, including increased engagement of external experts to assist in the analysis and determination of the appropriate presentation of significant or non-routine transactions, and documentation thereof.

Management has subsequently operated the control effectively multiple times. Management have therefore concluded that the Material Weakness has been remediated of December 31, 2023. Management has determined that the transaction in question has been presented appropriately in the consolidated financial statements in accordance with accounting principles generally accepted in the United States of America for the year ended December 31, 2023.

Attestation Report of the Registered Public Accounting Firm

Changes in Internal Control over Financial Reporting

Other than the changes related to the remediation activities related to the previously reported material weaknesses noted above, no other changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) occurred during the year ended December 31, 2023 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.