The combination of the two words 'secret' and 'patent' seems, at first sight, to be a contradiction. Secret means kept private, whereas litterae patentes, from where the English word 'patent' comes, are open letters from the sovereign conferring some right or privilege. And the letter is open, for everyone to read, so that everyone knows just what it is the sovereign has given away, and just what it was the subject had asked for. In the case of letters patent for an invention, the bargain between the sovereign (the state) and the subject (the inventor) is that the inventor gives a full description of the invention, which is then published, and, in exchange for this contribution to public knowledge, the state undertakes to grant the inventor a temporary monopoly so that the invention can be exploited, initially, entirely to the inventor's advantage.
There are, however, exceptions. Today any resident of the United Kingdom who applies for a patent to protect an invention may be told that the publication of the specification is prohibited. More than that, the publication, even the communication, of the idea described in the specification is prohibited. The penalties for ignoring this prohibition, or trying to get around it, can be severe. Patent applications that run into difficulties of this kind usually involve weapons, but the law is wide in its application. Section 22 of the 1977 Patents Act extended the powers of prohibiting publication to anything 'prejudicial to public safety'.
This book attempts to give the history of how 'secret patent' legislation developed in the United Kingdom. Its origins are surprisingly early in that the first case of prohibition to be found in the records occurred in 1855. The first Act of Parliament that specifically dealt with secret patents received royal assent in 1859. In tracing the thread of secret patents through the fabric of the history of inventions, patent law, and society in general, we come up against some interesting ideas and unusual people. Naturally, inventions that the state believed should be kept secret must have