SPIRENT COMMUNICATIONS PLC

Share Buyback Programme Update

London, UK - 3 July 2023: Spirent Communications plc ("Spirent", the "Company" or the "Group") (LSE: SPT), the leading provider of automated test and assurance solutions for next-generation devices and networks, announces that beginning today, 3 July 2023, it will commence the second and final £28 million tranche of the £56 million share buyback programme (the "Programme") that was previously announced on 3 April 2023.

As announced on 23 June 2023, the Company entered into a non-discretionary agreement on 23 June 2023 with Jefferies International Limited ("Jefferies"), acting as principal, to exclusively conduct the second and final tranche in the Programme on the Company's behalf (the "Agreement"). Jefferies will purchase Ordinary shares ("Ordinary Shares") up to a value, excluding expenses, of £28 million, and will make trading decisions under the Programme independently of the Company and in accordance with certain pre-set parameters. The Company obtained authority to purchase 61,113,015 of its own shares at its 2023 AGM.  After completion of the first tranche of the Programme, the remaining authority stands at 53,582,597 shares.  This second and final tranche will end no later than 3 November 2023.

The Programme will be conducted in accordance with the general authority to repurchase shares granted by the Company's shareholders at the 2023 Annual General Meeting, Chapter 12 of the UK Listing Rules and the provisions of the Market Abuse Regulation 596/2014/EU as amended by the Market Abuse (Amendment) (EU Exit) Regulations 2019 ("UK MAR") and the Commission Delegated Regulation 2016/1052/EU as amended by Technical Standards (Market Abuse Regulation) (EU Exit) Instrument 2019 which both form part of the law of the United Kingdom by virtue of the European Union (Withdrawal) Act 2018. The repurchased shares will be cancelled. The Ordinary Shares will be purchased on the London Stock Exchange and/or on Aquis Exchange, Turquoise, BATS, Chi-X.

Spirent will announce any market repurchase of Ordinary Shares no later than 7.30am on the business day following the calendar day on which the repurchase occurred.

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About Spirent Communications plc

Spirent Communications plc (LSE: SPT) is the leading global provider of automated test and assurance solutions for networks, cybersecurity, and positioning. The Company provides innovative products, services and managed solutions that address the test, assurance and automation challenges of a new generation of technologies, including 5G, SD-WAN, Cloud, autonomous vehicles and beyond. From the lab to the real world, Spirent helps companies deliver on their promise to their customers of a new generation of connected devices and technologies. Further information about Spirent Communications plc can be found at https://corporate.spirent.com/.

Spirent Communications plc Ordinary Shares are traded on the London Stock Exchange (ticker: SPT; LEI: 213800HKCUNWP1916L38). The Company operates a Level 1 American Depositary Receipt (ADR) programme with each ADR representing four Spirent Communications plc Ordinary Shares. The ADRs trade in the US over-the-counter (OTC) market under the symbol SPMYY and the CUSIP number is 84856M209.  Spirent ADRs are quoted on the Pink OTC Markets electronic quotation service which can be found at https://www.otcmarkets.com/marketplaces/otc-pink.

Spirent and the Spirent logo are trademarks or registered trademarks of Spirent Communications plc. All other trademarks or registered trademarks mentioned herein are held by their respective companies. All rights reserved.

Cautionary statement regarding forward-looking statements

This document may contain forward-looking statements which are made in good faith and are based on current expectations or beliefs, as well as assumptions about future events. You can sometimes, but not always, identify these statements by the use of a date in the future or such words as "will", "anticipate", "estimate", "expect", "project", "intend", "plan", "should", "may", "assume" and other similar words. By their nature, forward-looking statements are inherently predictive and speculative and involve risk and uncertainty because they relate to events and depend on circumstances that will occur in the future. You should not place undue reliance on these forward-looking statements, which are not a guarantee of future performance and are subject to factors that could cause our actual results to differ materially from those expressed or implied by these statements. The Company undertakes no obligation to update any forward-looking statements contained in this document, whether as a result of new information, future events or otherwise.