Bruni CF92 

With thanks to John G for these pics and text:

"Bruni CF92: Italian version of the Relum HLP underlever air pistol by Bruni BBM. It differs from the Relum in having a rising breech block that automatically opens on cocking. Serial numbers suggest that it was made in considerable numbers, yet it is a rarely seen pistol. Probably made from 1992 onwards, as suggested by its name."