Image copyright Topical Press Agency Image caption John Logie Baird is best known as the inventor of television

Scottish inventor John Logie Baird is famous for being the first person to transmit live television images. But almost a decade earlier, during World War One, the Helensburgh-born engineer had success with another less well-known innovation.

The trenches of WW1 meant soldiers were constantly in muddy and wet conditions.

They could not change their socks as often as they would like and this led to an infection known as "trench foot".

If it was left untreated it could result in amputation.

The Baird Undersock promised to keep the feet of soldiers in perfect health.

His marketing of the product contained what he claimed to be "testimonials" from soldiers serving on the western front.

One from Corporal H.G. Roberts said: "I find the Baird Undersocks keep my feet in splendid condition out here in France. Foot trouble is one of our worst enemies, but, thanks to the Baird Undersock, mine are in the 'pink', and I think they should be supplied to all soldiers."

Image caption Baird used sandwich-women to advertise his undersocks

The product was so successful that it allowed him to give up his job as assistant mains engineer, supervising the repair of electrical breakdowns for the Clyde Valley Electric Power Company.

It was a job he described in his memoirs as "sordid miserable work, punctuated by repeated colds and influenza".

Baird, who was almost 26 at the outbreak of war in 1914, had tried to enlist but was deemed unfit for military service because of the range of illnesses he had suffered since childhood.

The idea for the undersock came from his one of his many personal ailments.

"He had cold feet," his daughter Diana Richardson says.

"His circulation was absolutely awful. He was always cold. I remember him wearing big thick heavy overcoats and he was still cold. He just could not get warm."

Stewart Noble, chairman of Helensburgh Heritage Trust, says: "He discovered that if he put newspaper inside his shoes that would absorb the moisture that always comes from the feet.

World War One at Home BBC Local Radio stories of a global conflict More WW1 stories from Scotland BBC - World War One At Home

"He came up with this idea of the Baird undersock, which was basically a sock sprinkled with borax. This would absorb the moisture that the foot gives off."

Baird's first attempt at marketing the undersock, an advert placed in the People's Friend, resulted in just one sale.

So he set about a range of unusual promotional devices such as a plywood mock-up of a tank carrying adverts for his product, which was pushed around the streets of Glasgow.

He also employed sandwich-board women to walk around with an A-frame promoting his undersocks.

"His innovation was having ladies do it instead of men," says his daughter.

Mr Noble says: "The fact that he was using women got him quite a bit of free publicity in the papers."

Ill health

In his marketing he skilfully mixed the promise of healthier feet with testimonials from soldiers in the British Expeditionary Force in France.

One from a 2nd Lieutenant G.H. stated: "They are the very things required out here. Woollen socks get sticky and 'clammy', and we can't get them washed. The Undersocks keep the feet and the ordinary socks fresh for weeks."

When undersock sales took off in the later stages of the war, Baird was making enough money to quit his job.

Mr Noble says he jumped before he was pushed.

Baird was never likely to have been promoted due to his constant ill health and the higher echelons in the power company frowned on his business sideline.

He was also responsible for causing a blackout across Rutherglen when he attempted to produce artificial diamonds by passing an enormous current through a stick of graphite.

Mr Noble says that in 12 months work on the Baird undersock he had earned as much as he would have in 12 years with the electricity supply company.

Ms Richardson says: "It was doing very well. It was booming but it was a one-man business.

"When he disappeared for six weeks the business disappeared too."

According to Mr Noble: "He was once again hit with one of his very bad colds so he just closed it down at that point and discovered that at the end of the day he had got something like £1,600 in the bank."

Baird saw this as an opportunity to move to a warmer climate and sailed off to Trinidad, where he experimented with jam-making.

This venture failed and he returned to Britain but his trip to the Caribbean may have sown the seeds for his most famous invention.

Mr Noble says: "There are tales of this fair-haired white man in a shack in the jungle with bright flashing lights.

"Whether or not that was him doing television experimentation I don't think anyone really knows but there is a possibility he was trying something out there."