I'm off to Rexon Stud at Lewdown in Devon on Sunday to work with the South West Shetland Pony Group. They are all keen on showing their ponies but want something else to do as well, so horse agility seemed a fun addition to their training regime.

I haven't had a great deal to do with Shetlands but I do have an abiding memory of grass-skiing with a little chestnut number a few years ago.

My husband used to work for the National Trust at Woolacombe on the North Devon coast and every year, three or four Shetland ponies would be seconded to our coastline to graze the cliffs. They came from Arlington Court where Shetland ponies were a feature in those days. Lady Chichester, the last private owner of one of my favourite trust houses, had kept Shetlands, Jacob sheep and parrots as pets. The parrots were no longer in residence, leaving their mark on the shredded curtains in the house, but the ponies remained.

The area they grazed on the coast was well off the beaten track so the ponies had to be led a few miles to their new pasture. It was on this journey that many a comic incident occurred.

Invariably, on entering the wide open spaces of the clifftop pastures, one would make a break for it. You could see the little darling preparing for this carefully thought-out manoeuvre. It would start to drop its head, planting its front feet as the hind feet began to shuffle under its rotund belly. Then with rocket propulsion, the back end would explode like a spring, propelling the front end up and forward like Eddie the Eagle off a ski jump. If you were quick and saw the tell-tale drop of the head, a swift tug would get it up and you could just about save the day. If you missed the moment, all hope was lost.

Have you ever watched a water-skier lift up out of the water as the power boat pulls away straightening the line to draw the skier smoothly through the water? Well this isn't what happened! There was no elegant smooth movement such as one sees on the water at Monte Carlo, oh no!

The pony was so prepared for his break for freedom that he was able to use all his strength to surge forward. This sudden G-force had an alarming effect on the unprepared handler.

His arms would shoot out in front of him, his head was thrown back bearing a look worthy of the big dipper at Blackpool. His legs would begin to pedal very fast as he realised that things were speeding up and if he was to remain at one with pony he needed to keep moving.

As a last-ditch attempt, the handler would attempt to ram his heels into the ground and throw his weight back.

And so for the onlookers, the fun began.

If the ground was in any way damp or muddy, Grass Ski Sunday – Shetland-style – was up and running as the handler slid along desperately trying to stay upright.

Anyone who had a relatively well-behaved pony could shout encouragement, either to the bolting pony or the handler or both. But if you had a pony with the devil in his eye, it took all your powers of persuasion to prevent the same thing happening to you.

The grand finale would come as the skiing handler would give up, plop forward and become a human harrow, spreading sheep droppings and mole hills until the pony gave up and started to eat.

So I'm looking forward to an action-filled day on Sunday. If you fancy coming along, we're there from 11am until 3pm. I can't promise any Ski Sunday Shetland shenanigans, but I think it'll be a lot of fun.