When you’re faced with a big red door, the only thing you want to do is open it and see what’s inside.

Gravesend’s Masonic hall in Wrotham Road has a giant padded one and behind it is the temple where members perform the rituals of the ancient society - some of which have been passed down since it was founded in London in 1717.

Anyone is allowed in to walk the black and white chessboard carpet and gaze at the dazzling array of mounted banners representing all but one of Gravesham’s 16 Masonic lodges, who have around 600 members.

But this is as close as any non-mason can get to learning what’s in the ‘playlets’ which initiated members act out, sometimes for up to an hour-and-half, or what constitutes the famous handshake unique to the male-only fraternity.

Freemasonary emerged when stone masons working on Canterbury Cathedral 300 years ago formed fraternal lodges to discuss their work.

The idea of establishing collegial units of up to 100 men caught the imaginaton of many non-stone masons, who became the first freemasons.

In a time when billions of people have voluntarily given up their privacy to a handful of internet corporations, freemasonry still prefers to retain some sense of mystery.

Philip South, 58, is chairman of the communications board for the east Kent province - one of 47 in England and Wales.

The mechanical engineer says: "If we openly told everyone about the rituals it would just take that edge off the tinge you get when you come into freemasonary.

"People do say ‘I’m so glad you kept the special bit for when I actually joined’.

"We are not a secret society, there is no need to hide, and we are open to anyone to join."

The fact I am shown around by three white men, of whom Philip is the youngest, does not do much to dispel stereotypes of freemasonary as an old boys’ club.

But to be fair it was during a week day, when many younger members are out working.

Roger Odd, 71, has been a Mason for 42 years, the last five of which have been as deputy provincial grandmaster for east Kent.

The pharmacist claims the fraternity is attracting younger and more diverse members.

He says: "In many lodges you would have Sikhs, Christians and Muslims sitting side-by-side.

"I think it’s fair to say all organisations are struggling to get the right people to come along and join them."

To be a mason you need to be over 21, believe in some sort of supreme being and not be in possession of what Roger calls a "serious" criminal record.

But having a womb will disqualify you, as women have their own entirely separate organisation.

Roger says: "We still have the ladies come to meet with us and we go to their meetings but the decision at the present time is that we will not mix the ladies and the gentlemen together as freemasons, because that’s the way it’s happened over the years.

"Change will come about but as we are at the moment, it’s quite clear the ladies like their space and we like our space."

The masons are rightly proud of the millions they raise for charity and the companionship they offer their 200,000 members in England and Wales and seven million around the world.

But there’s no ‘suck it and see’ with this lot - if you want to know what really goes on behind the big red door, you need to become one of them.