What date should i put in section 3.1 in Citizen Form

Hi,
I would like to know what date should i type in the NATURALISATION AS A BRITISH CITIZEN FORM in SECTION 3: RESIDENCE REQUIREMENTS
(3.1. Enter the day you first arrived to settle in the United Kingdom.)

I came to UK in September 2000 as a student.
In Spetember 2001 my company sponsored work permit and and my status was changed to Work permit holder (without going out of the country)

I got ILR last year and now its 1 year so i am eligible to apply for british citizenship


I would like to know what date should i type in the form

September 2000 when i entered the country as a student
or
September 2001 when my work permit started

Hope some one will help
Regards
Man1976

I think page 19 of the guide is pretty clear. It's when you first arrived to settle in the UK.

Many thanks for your answer. So this means Sept 2001 right when i got the work permit cause in 2000 i didnt come to settle here i was a student
I am right ?

Put the date 2000 as it is the first time you eneterd for your continous stay in UK. I did the same on advice from fellow members in the discussion board and NCS.