See for marrying your partner can come to london on tourist visa if you are planning to get married in london.
for Marrying in India you have to marry under Special marriage act.
The procedure and conditions are as mentioned below:
Conditions for a valid marriage under the Special Marriage Act:
Any two persons belonging to different religions may marry (not needed to change their religions)
Neither party should have a spouse living at the time of marriage.
Neither party should be suffering from mental disorder
Neither party should be unfit for procreation of children.
Neither party should be suffering from incurable insanity.
Neither party should be incapable of giving a valid consent (like unsoundness of mind).
Parties should not be within those degrees of prohibited relationship.
Age:
Bridegroom: 21 years
Bride: 18 years
Special Marriage Act: Solemnization and registration of marriage: (Procedure)
No religious ceremonies are required.
Parties to the marriages shall give notice to the Marriage Officer in the prescribed manner.
The marriage is solemnized a by Marriage Officer appointed by the Government.
The Marriage is to be performed after 30 days of this public notice and before expiry of two months from issue of notice.
The appointed Marriage Officer enters relevant information in the Register and issues a public notice of this information.
Before marriage the applicants and three witnesses shall sign a declaration in the form specified.
The marriage is thus completed and recorded in a book kept for that purpose. The entry is signed by the applicants and the witnesses.
Marriage shall not be complete and binding unless each party say the below mentioned words to the other in presence of Marriage Officer and three witnesses. I (X) take thee (Y) to be my lawful wife/husband (which shall be in any language understood by the parties).
Documents needed for marriage in India between an Indian and a foreign citizen under the Special Marriage Act:
Full birth certificate
Passport
The foreign party will need a visa for more than 30 days (we got married whilst I was on a 6 month Tourist visa)
Proof of address
Certificate of No Impediment/Single Status Affidavit
Passport sized photographs
Once you marry in India you can apply for visa and can take your partner with you.