The Advertising Standards Authority (ASA) has banned a "misleading" cinema advert from vegan campaign group Viva! that claimed 90 per cent of pigs are factory farmed.

The advertising watchdog delivered a clear message to Viva! to ensure any future adverts don't mislead the public over how animals are kept in "intensive farming environments".

Three complaints were made, two of which were upheld. ASA upheld the complaint that the advert was misleading because it featured farming methods no longer allowed in the UK.

It also upheld the complaint that the claim "90 per cent of pigs are factory farmed" was misleading.

A pig was featured running around in a field with a voiceover explaining she was called Hope and had been rescued by Viva! and this was her "dance for joy" for being outdoors for the first time."

Subsequent footage showed pigs indoors behind the bars of a very crowded pen. The voiceover stated: "it's something most pigs will never know as 90 per cent are factory farmed, Set them free. Try Vegan."

ASA said the claim was "likely to mislead" as it implied that the vast majority of pigs farmed in the UK were restricted to the indoors and never experienced the outside. It noted that 40 per cent of breeding sows were kept outside, and said it was not true to say those pigs and their piglets "would never experience life outside."

This is not the first time Viva has fallen foul of the ASA. Back in May it ruled that a poster linking milk to cancer was unsubstantiated, misleading and must not appear again.

The poster, displayed on buses in Bristol last September, featured an image of a cow's udder and included the claims "Some dairy industry facts we bet you don't know .... Most cows are pregnant when milking. That's why milk contains 35 hormones, including oestrogen .... some of these are linked to cancer. Milk is for babies, so let Viva! wean you off the teat!"

According to a report published by the Agriculture and Horticulture Development Board published last month, just two per cent of the population are vegans. Despite that, veganism receives a disproportionate amount of media attention.

Groups supporting veganism have programmes to train chefs in schools, colleges and hospitals to regularly cook plant-based recipes. They also use celebrities to gain more traction and to promote the logo "kind to animals is cool", as well as programmes for talks to school assemblies.

The majority of the UK's livestock farmers care for their animals passionately, and I believe it is time they spoke out more vociferously against misinformation. They need to show the public how they care for their animals, and one way to do that is to be open about their systems.

Open Farm Sunday, held in June, where farmers across the country volunteer to let the public see round their farms and how they care for their animals is a good example.

In addition, farmers through the auspices of the local NFU could invite organisations like Community Councils or Parent Teacher Associations onto their farms and tie it in with a farm feature in the local press.

The best approach is to reach out to school children, the consumers of the future. We already have an ideal organisation to undertake that task in the Royal Highland Education Trust (RHET). Through a network of 500 volunteers, the charity currently engages with 70,000 Scottish school children annually with a mixture of organised farm visits, classroom talks and local events. This equates to roughly 10 per cent to 15% of the total pupil population from age five to 18.

In addition to the volunteers contributing an estimated £1.2m worth of their time freely, The Royal Highland and Agricultural Society of Scotland (RHASS) support RHET to the tune of £200,000 annually. Unfortunately buses to take the schoolchildren out to the farms can cost between £150 and £800, depending on the number involved.

There simply isn't enough money to go round - but the First Minister's indicated there could be extra funding in her annual speech to the Scottish Parliament last Tuesday setting out the legislation intentions over the coming year.

In it she made a commitment to create more opportunities for primary school children to visit farms to raise their awareness of where their food comes from. How much the Scottish Government is prepared to offer remains to be seen, but extra funding is badly needed.