Notary public affidavit for OCI card

I apply for my son OCI card but they send documents back for notary public affidavit from UK. he don't have Indian passport as he born in India and got British passport in India please somebody suggest me where I can get affidavit or template.
Also in the letter they stated we need original affidavit and some supporting documents along with Indian passport, copy birth certificate. If birth certificate is being produced as the main proof of Indian origin , is issued at a recent date , the signature of the issuing authority has to be certified by first judicial magistrate in India. Please can some body clarify this .
Thanks

There are notaries in the UK who can draft an affidavit for you. Their prices vary so the best option is to refer to Yellow pages ( www.yell.com - search for notaries nearest to your postcode), find a notary nearby, contact them to check for prices based on your requirement. You can get your public affidavit drafted and notarised by them.

Google "Affidavit Template" and you will find quite a few templates. The problem you might have is which template should you use and I do not know the answer to that, hence my recommendation above.

Now the last paragraph (specifically this line - has to be certified by first judicial magistrate in India)) of your post makes me think you might need to get your public affidavit made and notarised in India. If you have friends or relatives in India, ask them if they can do this at a local court/by contacting a local lawyer on your behalf. They will then have to post the document to you in the UK.