RICHARD Casasola and his wife Leslie Colvin had been taking riding lessons for two or three years from Fiona McQueen, in Berwickshire, when she suggested they might enjoy the Borders Common Ridings. ''So we did the Peebles ride,'' says Richard, an Edinburgh doctor, ''it was super fun. Then we did the Lauder ride out, and brought a big crowd down from Edinburgh with food and champagne. There was a big fair and a gymkhana, there were loads of things going on. It was a brilliant day out.''

The Common Ridings which start in June and continue to the end of July are an integral part of Borders life. Each town from Jedburgh to Selkirk, from Lauder to Hawick, has a series of traditions that have evolved in different ways based on the ancient customs of riding round the town boundaries to ensure they have not been encroached upon by neighbouring landlords. Because they are so steeped in local history, the Common Ridings are an ideal way to become involved in the tradition of the towns and the countryside, to ride over land that would usually be closed to the casual rider, and to meet a variety of different people. But if, like Richard and Leslie, you want to get involved, how should you set about it?

Fiona McQueen teaches people to get fit and ride to a safe standard. ''I build up a plan, suited to each individual,'' she says. ''We begin lessons as near to the start of the year as possible. Some of the rides are quite long, and if people have not ridden before it will take more than a year before they are ready. Some riders take longer, perhaps two or three years to reach the right standard. I make sure my riders are safe and confident - I discuss it with them and decide when they are ready.''

Catriona McCaulay at the Dryden Riding Centre also teaches to a high standard, catering for all ages and stages, in both an indoor and an outdoor school. ''We have the advantage in that we do almost no riding on the roads,'' Catriona says. ''We have a lot of hill ground on our farm, which is perfect for experienced riders.'' Although Catriona does not teach at weekends when she is away competing herself, she runs accompanied rides on both Saturday and Sunday mornings. Highly recommended for the excellence of their horses and their high safety standards is the BHS-approved Kimmerston Riding Centre, near Wooler, Northumberland.

Dickie Jeffreys, who has a yard of about 30 ''safe and sensible'' horses, runs lessons and organised hill rides in the Cheviots and beach rides to Holy Island as well as lessons for beginners of all shapes, sizes, and ages.

But how should you set about hiring a horse once you have reached the desired standard of riding? Fiona McQueen, who would like to see legislation brought in to raise safety standards, urges caution when hiring a horse.

The festivals, she says are a great celebration, and a wonderful time, but accidents do happen. Nevertheless with care, the pitfalls can be avoided, especially by using

a reputable, licensed dealer who has a public-liability insurance. ''A lot depends on the dealers,'' she says. ''When you hire a horse you are not sure what you are going to get. Make sure the dealer knows the horse you are planning to ride.

''Sometimes the horse you have planned to hire goes lame, and they give you another one, maybe borrowed from another dealer and they may not know it. Make a verbal contract with the dealer. Go and see the horses, ride them and if you like a certain horse say you want that one.''

But which dealers are reputable? Leslie

Colvin went to Marjorie Renwick, at Ancrum, where she had the choice of a

wide range of horses, including quiet cobs and quality horses.

All Marjorie's horses are well behaved and are considered to be at the top end of the market - ''the Harrods'' of the common riding horses - even by her competitors. Some of them are home-bred, others are retired hunters whom she has known for many years. ''I like to see whoever I have got riding first,'' she says, ''to see if I have a suitable horse for clients, in terms of size and weight and experience. People usually come and

ride two or three times to try out horses.''

Bill Hughes, who trains a wide variety of horses, including point-to-pointers, in his yard near Galashiels was Richard Casasola's first point of call, at Fiona McQueen's suggestion. ''I tend to under mount people to start with,'' says Bill who does not offer lessons, but does provide escorted rides so he can judge his clients ability and then discuss their individual strengths and weaknesses. ''Don't go looking for a high-powered horse,'' he advises. ''Make sure you find one you are capable of riding. It is my responsibility to tell my clients if a horse is wrong for them, and make sure they are not over-mounted.''

For beginners, Bill suggests the smaller rides where you can progress at your own speed, recommending rides such as the Melrose Festival (June 14) which is very well marshalled.

''The smaller rides are less popular. Most people go for the bigger rides, but there is usually quite a crowd, although they have a great atmosphere and people are very friendly.''

Richard, whose enthusiasm for the Common Ridings, has grown to the extent that he learned to jump and took up hunting and is now looking for a horse of his own, says: ''On your first ride-out you don't know what to expect and then it becomes really enjoyable.'' But perhaps the greatest tribute should go to his teacher, Fiona.

On certain ride-outs it is traditional for participants to buy a bottle of champagne for every time they fall off. Fiona's pupils have never had to buy any champagne, although she adds that they get to drink plenty.

WHERE AND WHEN TO SADDLE UP

n What should you wear? ''There is no need to go overboard,'' says Marjorie Renwick, who strongly recommends a good crash hat, ''although it is not compulsory. You need a decent pair of boots and a comfortable pair of jodhpurs. You can get these at any good tack shop''.

n What does it cost? The prices vary according to length of the ride and the horse involved, but prices vary between #65 for the shorter rides to #95 at the main festivals. The price of lessons varies according to size of horse and rider.

n When and where?

n Hawick Common Riding. Ride-outs on Tuesday and Saturdays in the weeks leading to the Common Ridings on June 5-6. Contrary to belief, many of the rides are open to women.

n Selkirk Common Riding June 12.

n Melrose Festival June 14.

n Jethharts Callant's Festival, Jedburgh June 27, July 11.

n Kelso Civic Week July 12-18

n Lauder Common Riding July 25, August 1.

n Scottish Borders Tourist Board, Shepherd's Mill, Whinfield Road, Selkirk TD7 5DT Tel: 01750 20555. Fax: 01750 21886.

n Fiona McQueen can be contacted at Cowdenknowes Equicentre, Earlston, Berwickshire. Tel: 01896 848020. Accommodation.

n Catriona McCauley, Dryden Riding Centre, Dryden, Ashkirk, Selkirk, Tel: 01750 32208.

n Marjorie Renwick, Pinnacle, Ancrum, Jedburgh, Tel: 01835 830370

n Dickie Jeffreys, Kimmerston Riding Centre, Kimmerston, Wooler, Northumberland, Tel: 01668 21683.

n Bill Hughes, Netherbarn Riding Centre, Selkirk Road, Galashiels. Tel: 01896 850522.