We have a new paper on this: Goodridge, P., Haskel, J., Hughes, A., and Wallis, G., (2015). The contribution of public and private R&D to UK productivity growth, Imperial College Discussion Paper, 2015/03, March 2015, available at https://spiral.imperial.ac.uk:8443/bitstream/10044/1/21171/2/Haskel%202015-03.pdf
The abstract is
We estimate the contribution of public and private R&D to UK productivity growth on industry data, 1992-2007. R&D affects productivity growth via (1) R&D input, valued at competitive factor shares and (2) (Domar-Hulten weighted) industry TFP growth if there are (a) within-industry spillovers (b) between-industry spillovers and (c) spillovers from public-sector R&D to the market sector. Thus effects depend upon factor shares, spillovers and industrial structure. We estimate all these effects and perform counter-factual experiments such as e.g. additional government spending on the science budget, increased manufacturing R&D spending and the effects of such changes with a different industrial structure.
Our central estimate of the rate of return to public spending on science is 20%.
This the article behind my interview in the FT this weekend, http://www.ft.com/intl/cms/s/2/7da2852c-e3af-11e4-9a82-00144feab7de.html#axzz3XZSthOA9