"I JOINED in 1975. At the time my dad was breeding grasshoppers for genetic studies. The advantage for me joining at that age was that I met people who had the equipment I needed – moth jars, generators and lights."

Graham Collins is the entomological secretary of one of the borough's best kept secrets – the Croydon Natural History and Scientific Society.

Its members enjoy the use of a private library in Brighton Road – a museum hidden in the grounds of Chipstead Valley Primary School in Coulsdon – and they hold their meetings at East Croydon United Reformed Church.

But those aren't the only benefits: Mr Collins has come a long way since he joined the society, and is now the author of several books on his favourite subject.

"I'm the author of Butterflies Of Surrey, Larger Moths of Surrey and soon to be Smaller Moths Of Surrey.

"All of these books are collaborative efforts, and The Natural History Society contributes money to help them get published."

As well as local and natural history, the society also boasts experts in all the natural sciences, including geology, ornithology and meteorology.

Chris Taylor, an archaeologist, added: "I joined the society in the 1980s because its museum has a first-class archaeological collection and I have had a lifelong interest in this."

In 2008, he retired a few years early from being a tax accountant to do a masters degree in archaeology. After getting involved with the museum in 2005, he became the museum curator in April 2009.

"The society gives me the opportunity to study artefacts from the oldest to the most recent Stone Ages through its artefacts and archaeological book collection at the museum.

"The collection covers all other periods too, right up to the last century and this often sparks off research during the museum workshops that we have every Tuesday evening."

The museum holds an annual open day, which this year takes place on June 24.

Mr Taylor said he would recommend the society to others just for its excellent museum, adding "It provides an opportunity for those interested in working in museums to gain valuable practical experience.

"I have shown the ropes of museum work to several visitors during the last few years."

For others, such as Mr Collins, the society has been the starting point for a lifelong career in their chosen fields.

Recently, he conducted an impact survey for the Olympics on Box Hill, in Surrey.

"We found a butterfly called the small blue was breeding there, so that will have to be taken into account by the Olympic planning committee."

The society always welcomes new members.