When rains and floods started causing havoc in the UK and much of northern Europe last year, alarm bells sounded loudest for the impact on the potato crop.

Growers and suppliers struggled with delayed harvests and plantings as well as greatly reduced yields as a result of the unusually wet and cold weather. The effect on retail prices has been dramatic.

The average unit price of 639 fresh potato SKUs on sale across Tesco, Sainsbury’s, Asda, Morrisons and Waitrose over the past year has risen by 35p, or 21.6%, from £1.62 in February 2012 to £1.97 today [BrandView.com].

When looking specifically at those 150 lines that were stocked in the mults a year ago and are still stocked today, the inflationary picture becomes bleaker still: a massive 75%, or 113 products, have become more expensive in the past 12 months, with just 27 staying at the same price and 10 becoming cheaper.

Honey prices are under great pressure following sharp declines in production in the US and Australia. As both countries look for more imports to make up the shortfall in their domestic honey production - and demand in other regions remains strong - global honey prices have soared. At £2,450/tonne, Spanish honey is now nearly 20% more expensive than this time last year, and up 7% month-on-month.

Elsewhere in our tracker, prices are mostly falling year-on-year, as many dry ingredients return to more normal pricing levels after the high prices of previous seasons. Hazelnuts are down 29.7% year-on-year, as the market recovers from the poor Turkish crop in 2011, while desiccated coconut is down 33.2% as prices continue to fall from the highs seen in 2011, which were brought on by bad weather.

Meanwhile, peanuts are 38.8% cheaper thanks to good harvests forecast in the US and Argentina for this season.

All key varieties and pack sizes have been hit: for example, a 2.5kg bag of white potatoes has gone up by an average of 43%, from £1.35 this time last year to £1.93 now, while 1kg of loose baking potatoes has risen over the past year from an average of £1.34 to £1.48.

Overall, prices have risen in all five major multiples, but on some individual lines pricing strategies do differ significantly between different supermarkets. Take loose new potatoes - the average price across the mults has increased by 32.2% year-on-year, but this hides the fact that Morrisons has cut its price by 31% from £1.45 to £1 during that period, while Sainsbury’s doubled its price from £1.50 to £3.

However, it’s not all bad news in the potato fixture. In contrast to their white namesakes, sweet potatoes - which are not grown in significant volumes in the UK and therefore were not affected by last year’s miserable UK growing season - have become 8.5% cheaper over the past 12 months, falling from an average of £1.99 to £1.82.

This, of course, does not mean all sweet potato products are now cheaper than white potatoes, but in some cases a swap from white potatoes to the sweet alternative could net shoppers some serious savings. In Tesco, for example, 1kg of loose sweet potatoes now costs £1.29 - 21p less than 1kg of loose baking potatoes - while in Sainsbury’s sweet potatoes cost £1.28/kg compared with £1.50/kg for baking potatoes and £1.50/kg for loose Charlotte potatoes. A year ago, the sweet potatoes would have been the more expensive option.

With the Potato Council warning last week that UK potato stocks are down nearly 20% year-on-year - and the weather not looking too much better so far this year than it was in 2012 - sweet potatoes are well on their way to becoming the tuber of choice for budget-conscious shoppers.