The promise of Labour's military Keynsianism has not gone so well in the first year;
most of the extra money pushed into defence has gone on increased costs in the military supply chain, on housing costs & on maintaining the nuclear aspect of the UK's defence capabilities.
So the idea that increased spending would lead to an expansion of employment in the armaments sector (& by extension 'effective demand' in the UK) has, so far at least, come to little or nothing.