Bas is advocaat and partner, heading the Simmons & Simmons' IP practice in The Netherlands, based in Amsterdam. For more than 25 years, Bas’ practice covers the full range of intellectual property activities with a focus on patent and technology based litigation.

Bas and his team have a particular expertise in the life sciences sector, handling matters regarding medical devices, pharmaceuticals and biotech, and in the TMT sector, acting in matters regarding electronics, telecoms and software. Described by clients as "business-oriented, responsive and proactive", Bas acts before national and international courts, as well as the Dutch and European Patent Offices. He has been involved in all aspects of litigation, as well as other IP related issues such as licensing, prosecution strategy, negotiation of research and development agreements and the protection of trade secrets and know-how.

Bas is qualified as advocaat, registered with the Amsterdam bar and the Council of Bars and Law Societies of Europe. Bas is Advisory Board Member of EPLAW, the European Patent Lawyer’s Association, and he is recommended for his expertise in patents by all leading directories including Chambers, Legal 500, IAM Patent and IP Stars for many years. Client's praise the value of his advice and enthuse: "He's extremely thorough. He knows every detail, has a way of putting things into perspective and he manages his team very well."