Eddie, 74, and Jean Leishman, 72, have been foster parents for 33 years and have provided a loving home to children of all ages and backgrounds.
Many are now adults with children of their own, and still stay in touch with the couple, who they regard as substitute parents.
The Leishmans, from Cambuslang, Glasgow, became foster parents in 1980 while raising their own four children - but never imagined they would end up caring for 600 youngsters.
Mr Leishman, who used to work as a supervisor at a biscuit factory, said: "We were in church when we saw a sign that was advertising for people to sign up as foster parents.
"We both looked at each other and just went through with it. We wrote down the phone number, called them to say we were interested and that's how it all started.
"We already had children and thought another one would not have made a difference, but then it just got more and more."
The couple started off by providing a pre-adoptive home, where children would stay for a short period of time, until they moved in with their permanent adoptive parents.
They also cared for some children in their five-bedroom home on a longer-term basis and then took to emergency fostering, where they would get calls from social services at short notice.
Mrs Leishman said: "We've had kids from all over the world, from different backgrounds and different ages. A lot of them still stay in touch and phone us up and some even come to visit occasionally.
"We've had some hard times but the majority of the time has been good and now we just thought it's time to throw the towel and retire. We are now looking forward to long lie-ins, because we don't need to be alert all night long."
She added: "If someone asked me whether we would do it over again, I'd say 'yes - of course'."