Clennell, who has joined from the London Stock Exchange (LSEG), is experienced in supporting private equity-backed, high-growth businesses as well as M&A due diligence and the transaction life cycle. He has operated in the financial services sector for more than 25 years, previously working as CFO for post-trade optimisation service Quantile Technologies, where he helped with the fintech company's acquisition by the LSEG. Before that, he spent 15 years at JPMorganChase in London and qualified as a chartered accountant with Deloitte.

Clennell will oversee Attivo’s daily finance operations, guiding financial strategy, planning and maintaining fiscal stability, and collaborating with the executive management team. He will also lead the relationship with auditors, banks, and investors.

Stephen Harper, chairman at Attivo, said that Clennell’s “track record as an enabler of high-growth is exemplary,” adding that he will be a “hugely valuable addition to the Attivo team.”