Security should shape the pursuit before the certificate is ever mentioned. ISO/IEC 27001 is often treated as a certificate, a security questionnaire or something IT deals with after the bid is already taking shape. Bid Security by Design takes the opposite approach: information security becomes part of how the opportunity is qualified, captured, designed, written, reviewed, submitted, handed over and improved. This practical British field manual connects ISO/IEC 27001:2022, Annex A and APMP-aligned pursuit practice into one end-to-end operating model for secure bidding. It shows how to: identify security, privacy, certification and supplier risks before committing to a pursuit;control tender packs, classifications, workspaces, guest access and sensitive information;turn risk assessment and treatment into usable controls and a defensible Statement of Applicability;connect secure solution design, pricing, evidence and tender claims so they describe the same service;govern suppliers, cloud services, AI tools, remote work and external contributors;write security responses from controlled evidence rather than generic assurance language;structure independent review, verification, release and secure submission;handle clarifications, negotiation, incidents and post-award security handover;apply all 93 Annex A controls through the practical lens of bid and proposal work;monitor, audit, correct and improve the secure-pursuit system; andbuild a working secure-pursuit ISMS through a practical ninety-day implementation route.The field toolkit includes an ISO/IEC 27001 clause-to-bid crosswalk, a complete Annex A 93-control bid crosswalk, an APMP-aligned lifecycle map, working process packs, risk and Statement of Applicability tools, audit questions, realistic security scenarios, opportunity-specific control plans, role guides and a practical security scoreboard. Written for bid managers, proposal managers, bid writers, information-security and quality professionals, commercial leaders, SMEs, consultants and larger organisations that need security to operate inside the pursuit rather than around it. A certificate can support assurance. This book is about making the operating evidence behind the claim strong enough to survive the deadline, the evaluator and delivery after award.