YOU can just imagine it. Someone gives you a painting as a present, but your walls at home are hoaching with canvasses, so you stick it in a cupboard where it languishes for years.

Not normally for 130 years, to be fair, but the royal family is not a normal family. At least they knew where the painting was and they were happy to show you it.

Perhaps I should explain. Back in 1888, Glasgow held its first International Exhibition. The Victorians liked to show off how good they were at making things and conquering countries so an exhibition of Britain's prowess in the arts, sciences and industry was held at Kelvingrove. The then Prince of Wales, a decent cove who had to tour the world opening exhibitions and suchlike while his mother reigned on and on – yes, I know, sounds familiar – came along to open it, and was presented with an album of paintings and sketches by members of Glasgow Art Club.

His staff popped it into the Royal Collection at Windsor Castle where it was "kept in storage", which is nicer than saying they bunged it in a cupboard. But they looked after it, and knew where it was.

So when Glasgow Art Club, that old-style yet friendly club in a discreet building (as all good clubs are) on Bath Street, decided they should mark their 150th birthday with an exhibition of the work of members past and present, they wondered if they could rummage around the Royal Collection. Well, perhaps not quite rummage, but the Windsor Castle staff were delighted to help.

Art consultant Robert Ferguson went down to Windsor with club president Efric McNeil where they made a delightful discovery. Ferguson explains: "Among the drawings and paintings was a small watercolour by Sir John Lavery which had never been seen before. It is not even mentioned in his catalogue raisonne."

You see people who know their art can throw French phrases into their conversation quite naturally. An artist's catalogue raisonne is simply the official list of all their work, and the painting owned by the royal family was not there. Entitled Queen of Scots at Langside – it is Mary after the Battle of Langside in Glasgow. I've often thought it strange that Glasgow makes so little of the only famous battle to have taken place in the city. It's historically significant as after the battle Mary fled to England, where she was captured and eventually executed.

Anyway, the painting is a little beauty. As McNeil says: "It looks so fresh. It's as if it was painted just a couple of days ago." That's one of the benefits of keeping it in a cupboard out of sunlight.

Lavery was born in Belfast but came to Glasgow to find work, initially as a printer. His passion was art though and he became a celebrated portrait painter while a member of the art club. "Put his wife on Irish banknotes," says Ferguson.

What? But it's true. When Ireland won independence, Lavery was asked to create an image of a female personification of Ireland for the new Irish banknotes. It was a bit of mythology he had to come up with, but he modelled it on his wife. She was on banknotes from the 1920s up until the 70s.

Now that's how to impress the wife.

Anyway, Lavery's painting of Mary, Queen of Scots galloping ahead of her troops astride a white charger with a red cloak billowing behind her will take pride of place in the summer exhibition celebrating the club's 150 years. But there is much else to like in the exhibition. I've always been drawn to the club's painting of a young woman in uniform who stares confidently out of the image, much like Lady Agnew of Lochnaw in Sargent's portrait in the Scottish National Gallery. She was known simply as Cherie for some reason, but Ferguson did a spot of research. "Someone looked at the painting and called her Cherie, and the name stuck. But she is actually Lance Corporal Margot Millen of the Australian Ambulance Corps. She was stationed in Glasgow during the war and the art club invited a lot of military staff stationed here as their guests.

"Margot, I'm told, was very popular among the club members."

The picture was painted by Hugh Adam Crawford, who taught at Glasgow School of Art. Many a lecturer was a member of the art club and would skip down the hill from the art school to have a long lunch. "What is the old saying?" says Ferguson mischievously. "'Don't ask a tutor anything after 11am.'"

Ah yes, club members. Now many folk will think private clubs are a throwback to a time of stuffiness, privilege and class distinctions. There used to be 140 or so clubs in Glasgow, but now there are two, if you discount all the bowling clubs, golf clubs and so on. Older business types will fondly recall the Royal Automobile Club in Blythswood Square, now a hotel, when it served a damned fine house claret at lunchtime rather than concentrating on fixing flat tyres as the RAC does now.

There is the discreet Western Club in Royal Exchange Square, but I've never been invited there, unlike the more welcoming art club which allowed the Glasgow Herald reporters to hold their Christmas lunch there decades ago when Herald journalists were the type of people who could party in a Rabelaisian manner while actually being able to quote Rabelais. My favourite is: "When I drink I think; and when I think I drink."

Glasgow Art Club began as a regular meeting of artists in 1867, and later, many of the artists who became known at the Glasgow Boys joined. The growing membership needed a permanent home and the two townhouses in Bath Street were bought in 1892.

The membership then became a combination of artists and lay members who were often doctors, lawyers and business folk such as Lord Macfarlane who have an interest in, and a love of, art. Writers and poets joined too, including Para Handy author Neil Munro, playwright James Bridie, who helped found the Citizens Theatre, and eccentric adventurer Cunninghame Graham, who somehow helped establish both the Scottish Labour Party and the Scottish National Party. Mind you, we've seen a few folk recently dodge between both parties.

That combination of artists and lay people gave the club a more raffish air than other establishments. As member Billy Connolly once put it: "The Glasgow Art Club sold me an inordinate amount of alcohol and then the bastards banned me for unruly behaviour, but being renowned for my kindness and compassion I forgave them and since my reinstatement I have spent many happy hours in their salubrious surroundings dunking digestive biscuits in my camomile."

So go up to the door at 185 Bath Street and ring the bell. You are welcomed in to a hallway just like many a Victorian house with doors leading off in all directions. To the right is the dining room, and even before you enter it your eyes are drawn to a Hornel painting inevitably of little girls in a field. Like many folk I have a Hornel print on my wall, but this is an original.

To the left is a pokey little bar space. But that's its appeal. It means that members who stop by for a drink are squeezed in among other members so you all become part of one loose group with conversation flying around the bar with everyone joining in.

Artists you see, can be quite disputatious, holding strong views, and the discussions around the bar can sometimes soar. As artist Dugald Cameron once put it: "I recall a debate held in the gents with Dr Tom Honeyman, one-time boss of Kelvingrove Art Gallery, over whether a chair could ever be considered a work of art. He didn't think so, but I did – or was it the other way around?"

So we can often see an eclectic mix of members and guests at the art club. That's what Buffalo Bill and Dracula author Bram Stoker have in common – they have both been guests at the club.

Pass the bar and go through the swing doors into the Gallery. It's a show-stopper. Apart from its length, it is a bright room with glass ceiling and a frieze by Charles Rennie Macintosh running along the walls. When John Keppie designed the interior of the art club in 1892, overseeing the merging of two townhouses, young Charles was his assistant. In fact there is a painting by Keppie and floral sketches by Mackintosh in the new exhibition. Architects back then were not using computers, of course, and were often gifted artists using sketches and paintings to show their clients what they envisioned.

One sketch in the Gallery catches my eye. It looks like the City Chambers, but is somehow not quite the City Chambers. "It is a sketch submitted when there was a competition to design the City Chambers," says Ferguson. "It didn't win, but it is similar to the winning design, although it looks more French in style."

My other favourite painting is not even in the exhibition. It's of a very decorous, elegant woman. The story I was once told was that it was donated to the club by the second wife of the subject's husband, who couldn't stand looking at it in her house. But I think I was in the pokey wee bar when I was told the story, so wouldn't swear to it.

Go and see for yourself though. The exhibition is open to the public, is free, and runs from Monday to Saturday, 11am to 4pm, until the end of July. Just ring that bell at 185 Bath Street and see a part of Glasgow away from the raucousness of elsewhere.

After all, if it's good enough for Buffalo Bill and Billy Connolly, what's not to like?

Glasgow Art Club, 185 Bath Street, Glasgow. Visit