Citizenship Application

[st helena]

Hi I am about to apply for my naturalisation after holding my ILR for one year and I have below questions and really appreciate any help :
1- My residency on student visa , does it count towards 5 years required residency in the UK ?
2- Can I prove my residency only by sending my home country passports which shows I haven't left the UK over the past 5 years ?
3- Can I ask my ex-teacher in the college to sign my application as a professional referee , allthough he is no longer a teacher ?
Thanks for your help

[CR001]

1. Any legal stay in the UK counts towards the 5 years.
2. You have to send your passports.
3. If he is no longer a teacher, does he do something else or retired? Full list of acceptable referees in this link : https://www.gov.uk/government/uploads/s ... ersons.pdf