British Biotech and MerLion Pharmaceuticals establish collaboration for discovery and development of anti-bacterial drugs

-- Research to focus on bacterial ribosome targets --

Cambridge, UK, and Singapore – British Biotech plc (LSE: BBG, NASDAQ: BBIOY) and MerLion Pharmaceuticals Pte Ltd., a Singapore-based drug discovery company, today announced that they have signed a two-year research agreement to discover and develop new classes of anti-bacterial ribosomal inhibitors from natural sources. The collaboration will combine British Biotech’s expertise in ribosomal biology and structure-based drug design, including site specific assays, crystallography and NMR technology (acquired through its recent merger with RiboTargets Ltd) with MerLion’s extensive collection of natural product samples, its high throughput screening capabilities and natural product and medicinal chemistry expertise. Identification and characterization of lead candidates from MerLion’s natural product library will be performed using British Biotech’s proprietary ribosomal assays. The two companies will jointly progress selected lead compounds through initial pre-clinical development and will share in the intellectual property generated. Simon Sturge, British Biotech’s Chief Executive Officer, commented: “Collaborating with MerLion enables us to apply our extensive understanding of the bacterial ribosome and its potential as a novel target for anti-bacterial therapy to one of the world’s most diverse libraries of natural products. We look forward to a productive relationship with MerLion.” Dr Tony Buss, MerLion Pharma’s CEO, commented, “We are very pleased to be working with British Biotech and anticipate a successful collaboration that will contribute to better understanding of bacterial infection and improved treatment in this important therapeutic area.” ---ends---

British Biotech plc   Simon Sturge, Chief Executive Officer Tel: 01223 895555 Northbank Communications   Peter Colley Tel: 01260 296500 Brunswick   Fiona Fong Tel: 020 7404 5959     MerLion Pharmaceuticals   Dr Tony Buss, Chief Executive Officer Tel: 00 65 6773 7071   e-mail: enquiry@merlionpharma.com

Enquiries Safe Harbour statement: this news release contains forward-looking statements that reflect the Company’s current expectations regarding future events. Forward-looking statements involve risks and uncertainties. Actual events could differ materially from those projected herein and depend on a number of factors including the success of the Company’s research strategies, the applicability of the discoveries made therein, the successful and timely completion of clinical studies and the uncertainties related to the regulatory process. About British Biotech British Biotech plc, a biopharmaceuticals company listed on the London Stock Exchange and on Nasdaq, is building a portfolio of discovery projects and clinical products, both internally and through the acquisition of and merger with other companies. The company currently has two product candidates in Phase II of clinical development, two products in Phase I, one in pre-clinical development and eight research programmes. The company will seek to involve corporate partners for later-stage development and commercialisation of its products. The merger of British Biotech and RiboTargets Holdings plc was completed on 23 April, 2003. More information about British Biotech, including details on the merger with RiboTargets, may be found at www.britishbiotech.com About MerLion Pharmaceuticals MerLion Pharmaceuticals Pte. Ltd. is a privately held Singapore-based company, focusing on the discovery and development of new drug candidates from natural sources. The company's assets and capabilities include an outstanding natural product sample collection, advanced high throughput screening technology, assay development and medicinal chemistry capabilities. MerLion Pharma collaborates with leading pharmaceutical companies, biotechs and research institutes to identify and develop drug leads in a wide range of therapeutic areas. The company's other current collaboration partners include Abbott Laboratories, Athelas SA, Fujisawa Pharmaceutical Co. Ltd, Genome Therapeutics, Johns Hopkins (Singapore) Pte. Ltd., KuDOS Pharmaceuticals, Merck and Co., the National Cancer Centre (Singapore) and NovImmune SA. MerLion Pharma is also developing and commercializing lead compounds emerging from its own discovery programmes. More information on MerLion Pharma can be found on the company's Web site at www.merlionpharma.com .