The rapid development and adoption of Artificial Intelligence (AI) and Machine Learning (ML) technologies have brought significant opportunities and challenges. While AI has the potential to revolutionise industries and improve lives, there are growing concerns related to privacy, security, fairness, transparency and the environmental footprint. The Olympics motto "Faster, Higher, Stronger" also applies to recent impressive AI advancements, but now is the time to update it to "Lighter, Clearer, Safer". We propose ACHILLES to build an efficient, compliant, and trustworthy AI ecosystem. At its core is an iterative development cycle inspired by clinical trials encompassing four modules. It begins with human-centric methodologies, followed by data-centric operations, model-centric strategies, and deployment-centric optimisations. It returns to human-centric approaches, focusing on explainability and model monitoring. This iterative cycle aims to enhance AI systems' performance, robustness and efficiency while ensuring they comply with the legal requirements and highest ethical standards. Another innovation is the development of an ML-driven Integrated Development Environment (IDE). The ACHILLES IDE will facilitate seamless integration between the iterative cycle's modules, enabling users to develop efficient, compliant, and trustworthy AI solutions more effectively and responsibly. The project aims to significantly impact European AI development, aligning with the region's guidelines and values. Through innovative techniques and methodologies based on the collaboration of a multidisciplinary team of 16 partners from 10 countries, ACHILLES will foster a strong AI ecosystem that respects privacy, security, and ethical principles across various sectors. By validating the results in real use cases (including healthcare, ID verification, content creation and pharmaceuticals), ACHILLES will showcase its practical applicability and potential for widespread adoption.