I'm almost certain that two of my Italian ancestors never naturalised in the UK. Pietro Speroni and Rosa Anna Speroni (maiden name Pietronave) are shown in the 1911 census as Italian and not having naturalised.
I have already contacted the National Archives in the UK and they have found no record of naturalisation. However, they do not issue certificates confirming this. I am having trouble finding out who would issue these certificates. I know the UKBA issue these from 1986 onwards but I don't know if they do before this date? Does anyone know?
I wrote the UK National Archives and received a letter confirming that they had no record of my great-great-grandfather's naturalization. The letter was on UK National Archives letterhead and explained the specific archives that were searched. I e-mailed the Italian consulate in London, assuming that they probably deal with letters of no record for the UK more often, and they confirmed that the letter that I received is sufficient.