The Northleach Horror (2016)

1941. Mild-mannered linguist Enzo McWheattie is summoned by his old friend Whitsuntide, a deranged scientist working for the war effort, to a secret bunker under the Cotswolds. McWheattie, a lovely man, is completely oblivious to the fact that his “great friend” is a monomaniacal sociopath.
Whitsuntide’s huge subterranean machine, powered by all the electricity left over from the London blackout, is designed to summon the spirits of dead British spies so he can debrief them and discover what they learned prior to death. But so far, no one has been able to understand the ghost he’s raised.
McWheattie tries to interpret the dead voice, but an unpleasant surprise awaits the team, as the spectre, supercharged with megavolts, is not the friendly spirit they had been hoping for...