The article is devoted to the consideration of two basic procurement methods of military products by the UK Ministry of Defence: an open competition or competitive contracts and single-source procurement or non-competitive contracts. The UK has considerable experience with such contracts in the field of defence and security. In addition, the UK is consistently among the top ten countries in terms of military expenditures, holding the fifth-seventh place in the ranking. The UK is also the largest producer of military equipment not only in Europe, but also in the world. This article discusses the mechanism and regulatory framework of open competition and non-competitive procurement. The main changes of recent years related to the reform of the single-source procurement are analyzed. It is concluded that an open competition is a priority method, however, taking into account the specifics of the defense products market, non-competitive procurement are often the only acceptable ones. The efforts of the UK Ministry of Defence to improve the procurement mechanism here are aimed primarily at receiving value for money as close as possible to what could be received in a competitive market.