The head of the Gay Police Association (GPA) received a death threat after a row erupted over an advert the group put in a national newspaper.
The advert appeared ahead of the Europride parade
The advert blames religious beliefs for a rise in homophobic attacks and shows a bible next to a pool of blood with the slogan "In the name of the father".
Ch Insp Paul Cahill was sent an e-mail saying he would be "struck down".
The GPA said it had received a number of homophobic e-mails which could be used in a criminal investigation.
A spokesman for the GPA said since the advert had been in the press the group had been sent about 150 e-mails, some of which were supportive but others which were offensive.
The sender of the e-mail to Ch Insp Cahill proved they knew where the officer lived by including his postcode.
As well as saying the officer would be "struck down in God's name" the e-mail also said his "days on this earth are numbered".
Ch Insp Cahill told BBC London: "Many of these e-mails are signed, they come from identifiable email addresses.
"Some people have even put their home addresses on them in the complete confidence it's OK to send explicitly homophobic and threatening e-mails to another person, police officer or not.
"This ad was about provoking public debate about a very human social issue and this is what it's done.
"It was never our intention to recklessly offend people of faith and we don't believe that's the case.
"The number of e-mails of support we've received from Christians is as substantial as the number of critical e-mails we've received."