It's a fair bet that with the season of Burns suppers underway there will be a fair amount of haggis eaten in Scotland over the next couple of weeks.

Haggis is one of the few occasions Scots tuck into offal, as traditional haggis recipes mince the sheep's pluck - the heart, liver and lungs - with onion, oatmeal, suet, spices and salt and then stuff the mixture into a sheep's stomach.

Today consumption of offal is low in the UK, however it has not always been so. In earlier times offal was consumed by both rich and poor. During the Second World War when rationing restricted the availability of many goods, it was regularly eaten, but over the last 40 years there's been a considerable change in its popularity.

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In 1974, the weekly per capita consumption of offal in the UK was 51 grams, but by 2015 the per capita consumption was just 4g a week, a drop of 93 per cent, according to data from Defra (Department for Environment Food and Rural Affairs).

Liver is perhaps one of the best-known edible offals. In 1974 the average per capita consumption of liver was 36g, however by 2015 this figure had fallen to 2g. UK consumers are becoming very fussy about what they eat.

Elsewhere in the world there is a growing demand for all kinds of offal, or the so-called fifth quarter of an animal. Last November one of the UK's largest food producers received official notification to start supplying pigs' trotters to China following a successful inspection by Chinese authorities. Two further facilities in Northern Ireland have also received the first ever approval to export all cuts of pork, including trotters.

China has been identified as a "very high" potential market for UK pig meat exports and is already the UK's biggest customer outside the EU, importing 40,000 tonnes of UK pork and 36,000t of UK offal in 2016.

My mother, who came from Burnley in Lancashire, used pigs trotters to make stock for lentil soup, and then ate them. She also regularly cooked onions and tripe, and Lancashire hot-pot that used cheap cuts of lamb like the flank. My favourites were casseroled oxtail and oxtail soup. While oxtail may not be top of many shopping lists in the UK, it is much more popular in South Korea, China and Indonesia.

Perhaps my most adventurous attempt at eating offal was when I tried andouillette in a French restaurant. It's a sausage made of intestines that had such a strong, distinctive smell of the animal's colon that I let myself down and spat it out.

In addition to well-known offal like kidneys and tongues there are several types that few will have heard of, such as sweetbreads. They often come from either calves or lambs and are the thymus or pancreatic gland. They are creamy with a delicate taste, but sadly there is little demand for them in the UK so they often end up as pet food.

If you have a dog you may at some point have bought a paddywack, or ligamentum nuchae. It's the strong elastic ligament that links the head to the shoulder. Paddywack and leg tendons used to be rendered, however, in addition to being treats for pets both are also popular in the Far East for human consumption.

Then there is the pizzle, or penis of an animal, which is also suitable for human consumption although not commonly eaten in the UK. Once dried, pizzle can be turned into a paste, or even mixed with alcoholic drinks. In Jamaica, bull pizzles are commonly referred to as cow cods and are used to make soups. Pizzle is also commonly used in Chinese medicine due to many perceived benefits.

There are big financial incentive to make more of red meat offal which was worth £41m to Scottish processors in 2016. After all, why pay to have something rendered that could be sold as food?

In 2016 in Scotland ex-abattoir beef offal sales were worth approximately £70 per head or £33m in total, sheep offal sales were £6.50 per head or £7.5m and pig offal sales came to £2.50 per head or £750k in total.

According to HMRC the UK exported 35,800 tonnes of offal in the first 11 months of last year worth £42.8m. Frozen pig offal, excluding livers is the major UK export - 19,000t in January to November last year - of which nearly three-quarters went to China and Hong Kong.

I believe it is important to show respect for the animals we slaughter by eating every part of them.