The pair, from Hampshire, named the Purely Blue Brothel in Auckland, New Zealand, as the world's perfect.
According to Jean, it was 'lovely, just like a hotel'.
"The approach taken in New Zealand was the best we found," Mrs Johnson, 62, a housewife from the leafy village of Four Marks, told the Daily Echo newspaper in Southampton.
Prostitution and brothel-keeping are legal in New Zealand.
The duo's campaign to legalise brothels in UK to protect prostitutes came after five street call girls were murdered in Ipswich.
Landells said of New Zealand: "They legalised brothels five years ago and two girls can work together and of course that makes it much safer.
Landells said she was not seeking to condone or condemn prostitution, just to make it safer for the women involved in it.
Back in Hampshire, other members of their WI group "kerb-crawled" through Southampton streets as well as visiting some of the county's estimated 600 brothels to see the "horrendous" working conditions for prostitutes.
The women were so shocked at what they found they have launched a campaign to highlight the plight of Hampshire's prostitutes.
"One of our team members went in to brothels in Hampshire to see first-hand the working conditions these girls are faced with," said Mrs Johnson. "What we saw was absolutely terrible - it was heartbreaking. We saw lots of girls on the streets, working in the most terrible situations.
"I saw two young girls working in one of the most horrendous parts of the city near an industrial area. The myth of prostitutes wearing short skirts and low cut tops is totally false - they were just wearing ordinary clothes, but they were in a desperate situation.
"If anything had happened to them, no-one would have known. There was another girl who was addicted to drugs, who felt she had to continue working as a prostitute to fund her habit. Sadly a lot of girls on the streets are addicted to drugs, probably as a direct result of their work."
Shirley said: "Some people say prostitution shouldn't happen, but it does. Providing somewhere for it would help to make the girls safer."
The women's campaign will be the subject of a documentary to air in Britain later this year.