dunnhumby co-founder Edwina Dunn — "over the next 10 years Clubcard and dunnhumby made an extra £60bn of sales" (DS, quarantine)

Claim. dunnhumby co-founder Edwina Dunn has recalled publicly that Clubcard and dunnhumby produced "an extra £60bn of sales" over the decade following the 1995 launch.

Source. Edwina Dunn participant recollection, recirculated via Computer Weekly and other trade press; primary verbatim source not independently traced this pass.

Confidence. Directional-self-report (DS). Co-founder claim — strong incentive to anchor a large figure to the programme she helped build and later sold to Tesco for ~£93m (and then to other partners later).

Caveats. The £60bn figure has no independent audit trail in publicly available sources. Counterfactual ("what would Tesco sales have been without Clubcard?") is unrecoverable from the participant-authored sources. Quarantine: do not state as neutral fact; attribute to Dunn explicitly if used.

Implication / use. Use ONLY with attribution and incentive-flag. Never as supporting magnitude evidence for "data-driven CRM produces $X." This is a participant's recollection, not a measurement.