What can we Learn about UK Fiscal Multipliers from 140 years of Policy?

I use a novel dataset compiled from archival research in the UK Parliament with 140 years (1879 to 2018) of in-year government spending shocks, which are unlikely to be anticipated due to the UK's idiosyncratic budget process - an assertion supported by statistical tests on the shocks. I find a multiplier of 0.44 on impact and 0.47 in the long-run, along with some evidence of larger stimulative effects from civil spending shocks at short horizons relative to military spending shocks. Effects on other macroeconomic variables support results from New Keynesian workhorse models, as well as negative consumption effects found in empirical studies using large military spending shocks. I also find evidence of larger multipliers in states of high slack and with lower openness to trade, but my estimates do not corroborate empirical findings of larger multipliers with lower debt-to-GDP ratios or fixed exchange rate regimes.