Video report from ITV News Meridian's Abigail Bracken
The four marmosets kept in this garden in Rochester have all been re-homed from owners who couldn't cope with them.
Now their new keepers say they are receiving regular calls for help from owners struggling with marmosets kept in tiny cages, or who've bought monkeys removed from their mothers too young.
Lisa-Marie Bearman, Marmoset owner
Marmoset owner, Lisa-Marie Bearman, says: "To be taken from their mums and dads just so these people can have these pictures and sell these little monkeys for £1,000 to £1,400 and have this little hand reared monkey they can just have as a little trophy".
Marmoset owner, Matthew French, says: "They can't have the primate in the house with young children because they are very clever and they do escape out of their enclosures".
"They can easily, like I said, they don't show any sign of friendship straight away they just want to get away from you and if you upset them they will bite you".
Marmosets need lots of outside space, the right diet and not to live alone.
They are the most common kind of primate kept as a pet and they can live between 7 to 12 years in captivity but they can live a lot longer, up to 20 years.
The government has been consulting on plans to ban primates, like marmosets, being kept as pets. But is proposing licensing some keepers, which the RSPCA says must not happen.
Ros Clubb, RSPCA
Ros Clubb, from the RSPCA, says: "The proposals are that there would be a licensed keepers who would be allowed to continue to sell and breed primates between themselves and we really can't see that that is a good move for animal welfare or for clarity just moving forward".
"There's no need for that to happen except for very exceptional circumstances when it's part of a defined conservation breeding programme".
But this couple say any regulation needs to happen quickly, before more monkeys suffer.