The Conservative party used austerity rhetoric as a way to win votes, but they did not cut spending other than reversion to the mean after the high spending around 2008.

See here for international comparison of government spending as % of GDP (the second figure showing trends over time), UK is not an outlier:

https://www.imf.org/external/datamapper/exp@FPP/USA/GBR/CZE/...