hel please ,infos about uk visa (Rome)

good morning
im a congolese man,married to an italian woman,with the soggiorno and waiting for the residency that i should be getting really soon.i would like to know if i need a visa to go to the uk,and if yes where is the uk consulate/embassy? i have this number that i keep calling but cant get trough to anyone,just getting those recorded infos which doesnt help me much.
thank you