Ok Guys, i have got my answer and thought of sharing. Here is the excerpt from UKBA (now gov.uk) site
Degrees taught or researched in English
You’ll need to prove your degree was both:
taught or researched in English
confirmed by UK NARIC as the equivalent of a bachelor’s, master’s or PhD degree in the UK
You’ll need to provide your original degree certificate and 1 of the following:
- a printout from the points-based calculator with the equivalent level of your degree and the level of English
an original letter or certificate from UK NARIC confirming the equivalent level of your degree, plus an official letter from your university with your name and degree confirming that your degree was taught in English
an original and official certificate from your university confirming the degree was taught or researched in a majority English-speaking country (excepting Canada)
Therefore if your spouse has a degree which is on ukba calculator, you only need a printout of the calculator showing points awarded plus the original degree certificate. That's it, you are done.
Here is the url for more info.
https://www.gov.uk/english-language