It takes a trained eye – and hardy walking shoes – to spot ‘ghostsigns’, the fading remnants of hand-painted advertising on London walls.

But according to Sam Roberts, 36, of Maury Road, “Once you’ve started looking, you’ll get hooked on it.”

Sam has documented signs in their hundreds since 2007 on an online archive.

His passion for historic signs was sparked after a chance encounter in 2005, when he still worked in advertising, on Stoke Newington Church Street.

He said: “I spotted this old sign on a wall advertising a particular brand of fountain pens, Waterman’s Ideal Fountain Pen, and I thought: Wow. People used to paint these things! It really caught my eye.”

Sam began blogging in 2007 about the signs, which are mainly from the late Victorian era in the 1880s and 1890s, but were also prevalent in the 1920s and 30s. From 2009 he led a year-long national project for the History of Advertising Trust Ghostsigns Archive, with more than 150 photographers in more than 600 locations.

He has also received help from Victorian London and Hackney Archives, “an under-used resource and the home of where I’ve done all the research. It’s fantastic.”

He devotes time to finding work for sign writers, running educational workshops for people interested in the craft.

He said: “It’s still a very strong, thriving community in this country, though obviously a lot smaller than in 1910. Once every fruit and veg store had a hand-painted sign.

“It’s funny – my two worst subjects in school were art and history.”

But he’s not convinced the signs will be history any time soon.

Sam said: “We occasionally put up ‘RIP’ posts when we lost one. The counterpoint is they’re revealed too. Sometimes a billboard might come down and underneath it there’s a ghostsign. Older buildings often outlive new ones.

“One thing people get into is repainting them. There are highly controversial ones in York and Cambridge. City Council did a pilot project and the restored sign appears to bear little or no consideration of how the original looked. “It’s a shambles.”

Sam has recently written about the subject for new publication Monotype.

He also posts weekly on the site and writes for industry publications such as Ultrabold magazine, as well as more academic pieces for the Literary London Journal.

Many books published on the subject, he said, come from the US: “It’s much better there. There’s a lack of effort made in this country to catalogue old signs.”

Closer to home, Stoke Newington is a treasure-trove.

Sam’s favourite local ghostsign is still the Waterman’s advert, which has achieved local listing status in an English Heritage-backed project, alongside one for Bloom’s Pianos in Kingsland Road.

Walking tours have been well-received, with over 200 people attending since Sam first offered them last October.

The tours give local history and help participants develop an eye for signs in the cityscape, which are often not at ground level.

He said: “I tell them I want to ‘tune them into the frequency of ghost signs’.

It has clearly worked.

Sam added: “You become a magnet. People find this stuff and email and text you. A guy got in touch from Mildura on the edge of the Australian outback and shared an amazing collection of old photos.

“The internet has been great for bringing people together in this way.

“I’m probably turning into a bit of a snob. I must have looked at 20,000 photographs, deciding what’s in and what’s out. I definitely have a filter now.”

A fresh set of ghostsign walking tours has just been announced. For more information on the project and to book a tour, visit ghostsigns.co.uk.