Starting with a brief overview of trends in plant variety protection (PVP) in the UK since inception of PVP legislation, this paper assesses the strength of incentives for innovation provided by the PVP regime. We modify and extend models from the patent literature that attempt to infer the private value of innovations from the behaviour of titleholders in relation to the annual renewal of protection. Our results suggest that the average private return to protection from new wheat varieties is fairly modest and that the distribution of these returns is highly skewed. This implies that a large proportion of PVP certificates have very little economic value. The move towards stronger forms of protection for plant variety innovations and the (successful) clamour from the industry for imposition of royalties on farm-saved seed of protected varieties can be understood as a response to the declining returns from variety innovations in agricultural crops brought about by increasing competition and accelerated turnover of varieties. Anecdotal evidence regarding the declining viability of conventional plant breeding for agricultural crops in the UK is also supported by our results.