Pensioner Brian Behan is taking his campaign against marriage to a wedding fair - dressed as an undertaker.
Mr Behan, 75, founder member and secretary of the Anti-Marriage Society, will be warning young couples not to tie the knot.
He will be spreading his controversial message to hundreds of people via a megaphone during the event, in London's Olympia Exhibition Centre on Friday.
Mr Behan, of Newark Place, Albion Hill, Brighton, described marriage as "two people arguing and not having sex".
He said: "Marriage is not a word, it is a death sentence.
"It imposes on men and women a tremendous emotional strain."
In the past Mr Behan, brother of late Irish writer Brendan, has taken his campaign on to television.
He said: "I was for marriage when I was young but I changed my mind as I got older. It took about five minutes.
"Marriage as an institution is dying and I hope to bury it."
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