What's my VAF number? the same of the previous visa?

In my passport there are two stickers that I called my "visa". The first one says UK Entry Clearance on top and it has a VAF number. This visa/sticker was granted for my Mphil and it expired on 2007. The second sticker on a different page of the passport says "Residence Permit", it's reddish instead of yellowish and has no indication of VAF number.

Since the latest visa should be mentioned in my new application for TIer4 I am wondering how do I obtain the VAF number for this? Or is it the old VAF number valid for all extensions of the student visa?

What is the actual question and on which form that you need the answer to?

It is section 5 of the online application for student visa (general). The section is called immigration history and they say:

"You stated that you had made an application to the Home Office to remain in the UK in the last 10 years."

then date, refused or granted and Reference Number

Help provided for this question say.

Have you made an application to the Home Office to remain in the UK in the last 10 years?
Please enter your Home Office reference number which is prefixed with the first letter of your family name e.g. Smith = S123456.

I can't find anything like this and most forums in internet say this Reference number is actually the VAF.

I assume you are applying from outside the UK?

They mean the Home Office reference, the format for which they have explained, e.g. Smith S123456. This is not the VAF reference.

You would only have a Home Office reference if you had applied for leave to remain in the UK, and then you would only usually have a Home Office reference if you were refused or if your application involved correspondence with the UKBA. If you don't have a Home Office reference, and it doesn't allow you to put 'N/A' on the online form, then put something like A00000

If they ask for the reference number on your entry clearance they mean the red number on the top right hand corner on the vingette.