The first episode heads to the world-famous Brixham fish auction, which has been going for over a hundred years but is now experiencing the biggest boom in its history, turning over up to a million pounds a week. For sellers like trawler captain Alan Scales there is much at stake. He needs to get good prices for his fish or he can't pay his crew. Buyers range from big traders like Sean Perkes, spending tens of thousands of pounds a day on fish that will be exported round the world, to local fishmongers like Tracey Beer, battling to keep her shop afloat in challenging times. The programme explores how the Brixham trawler transformed the industry in the 1800s, allowing fisherman to go further and fish deeper than ever before.

The Royal Welsh Showground in Builth Wells, mid Wales, hosts the Welsh Cob Autumn Sale. In front of crowds of up to 3,000, the three-day event sees more than 400 horses go under the hammer. One of the UK's most popular horse breeds, Welsh cobs were once the national workhorses. Now they're in high demand for riding and showing, both in the UK and internationally. Buyers from Japan and Germany are regularly seen at the auction. For seller Marilyn Beach and granddaughter Robin, there's lots at stake. They have four horses to sell, and success will help ensure the future of the family stables that Robin hopes to run one day. Janet Alderton and daughter Jo need new horses for their riding school and know that if they can get what they need, they can change lives.

South west England is Britain's farming capital, producing more food than the whole of Scotland and twice as much as Wales. At its heart is Exeter Livestock Market, the biggest agricultural auction in the region. On a busy day they sell over 3,000 animals, from cattle to pigs, sheep to calves, in around four hours. It takes a whole team of auctioneers to do it. Turnover can be as much as ú700,000 a day. For Chris Creeper, selling four calves, there's a lot at stake. The young farmer, supported by wife Connie and three-year-old daughter Sophie, has only been farming a few years - margins are tight, and good prices at auction are vital. At the other end of the scale, buyer John Laramy, nearly 80, has been coming to this auction for 50 years.

Spalding Plant and Vegetable Auction in Lincolnshire is the oldest market of its kind in the UK, having started in 1948. There are three sales a week, selling as many as 1,000 bags and boxes of veg and up to 16,000 plants, shrubs and trees in a day. It needs two auctioneers to do it. The auction is here for a reason - a quarter of all UK veg and plant production happens in the Lincolnshire region, and in some areas one in four people work in agriculture.

Bala in Snowdonia, north Wales, is home to one of the UK's most important sheepdog auctions - the Bala Autumn Sale. Nearly 80 dogs are sold in a day, and good prices are expected. From prize champions to inexperienced pups with promise, the Bala sale draws in buyers from all over the UK and phone bidders from as far afield as Iceland and the USA. Terrible weather threatens to derail the day, but the auction soldiers on.

This programme spotlights the Welsh Cob Autumn Sale at the Royal Welsh Showground in Builth Wells, where 400 horses go under the hammer over three days. There is a lot at stake for seller Julie, one of the UK's top Welsh cob breeders and a former winner at the prestigious Royal Welsh Show. Buyer Alan Scales also has a lot riding on the auction, and as one of the biggest Welsh cob agents in Britain, he hopes to purchase 30 or more Welsh cobs on behalf of his many international clients. And renowned breeder seller Rob Manchip hopes to find good homes for the four horses he has to sell, before he downsizes with an eye on retiring.

This edition focuses on Exeter Livestock Market - the biggest agricultural auction in the West Country, which on a busy day can sell nearly 4,000 animals. Sheep seller Stuart Crang is bringing 80 sheep to market, and with sheep rearing being seasonal, he has to make the most of his income in the next few months, so prices are vital. Buyer Roger Heggadon has to take care he does not pay too much. With nearly 2,000 sheep on his farm, and another 100 to buy today, it is a volume business that needs a clear head at auction. In the pig auction, buyer Rodney Phillips needs to buy at least 100 pigs to supply over 40 regular customers - from butchers to wholesalers - across the West Country.

This programme spotlights Brixham Fish Market, established for over a hundred years, and currently turning over around ú30 million a year - more than any other English fish auction. It is a tough life for auctioneers John Rogers and Todd Crombie, who have a 4.30am start every weekday. Sellers like fisherman Matt Ould can also find it a tough life as well, with prices always unpredictable. Buyers at the auction range from traders like Josh Perkes, spending thousands of pounds a day on fish that will go to his many high-end restaurant clients, to smaller local businesses like Jackson Ltd, which has been in Matt Endacott's family for nearly 100 years.

This programme follows proceedings at the Bala Autumn sale - home to one of the UK's most important sheepdog auctions. Nearly 80 dogs are on sale today, to buyers from all over the UK and beyond. Auctioneers Glyn Owens and Elfor Morris must battle atrocious weather, while seller Emrys Jones, a veteran of the sale for whom training and selling sheepdogs is an important part of his business, hopes to get well over ú2,000 for each of his dogs at auction. His son Osian is helping his dad with the business and hoping to buy a young dog of his own at the auction, to train up and sell later. Seller Dewi Williams also needs to supplement the income from his small farm. He has been training sheepdog Jess for eight months, and he and son Goronwy have high hopes.

A focus on the Spalding Plant and Vegetable Auction in Lincolnshire, the biggest market of its kind in the country, hosting three sales a week where as many as 1,000 bags and boxes of veg and up to 16,000 plants, shrubs and trees are sold in a day. Farmer John Dix aims to sell nearly a tonne of potatoes, but there has been a national potato glut recently, so prices could be a worry. The Spalding Auction is vital for buyer James Dawson, who has a bustling fruit and veg stall in Scunthorpe Market. He must strike a careful balance between getting the stock he needs to keep the stall running and paying low enough prices to make a profit and pay himself a wage. And Charles Stubbs, a man with 10 garden centres to buy for, needs 4,000 plants, trees and shrubs to keep empire supplied.