The majority of indoor sows in the UK (around 95 per cent) farrow in conventional farrowing crates. There is pressure from a number of quarters – EU and national regulators, supermarket buyers and consumers – to improve the welfare of sows by adopting ‘‘free’’ farrowing systems. A DEFRA-funded project (under the acronym PigSAFE) conducted by Newcastle University and the Scottish Agricultural College (SAC) has developed and tested such a non-crate farrowing system. The trial monitored the costs and pig performance of over 450 sows which farrowed in either PigSAFE pens or conventional farrowing crates. The data generated in this work were used to construct spreadsheet-based budgeting models and linear programming (LP) models to assess the comparative economic performance of the two systems and determine the likely uptake of the new system. The results suggest that the cost of production under the new farrowing system would be about 1.6% higher than the conventional farrowing crate while pig performance was comparable in the two systems. A survey showed that UK producers were prepared to consider the new systems when renewing their farrowing accommodation, although the modelling exercise suggests that a price premium would still be required to ensure the viability of the new systems.