In May 1925 dozens of newspapers published a letter claiming that ‘it would be in the public interest to scrap the tram car’. Petrol-powered buses were more mobile and cheaper than trams, which should be banned from congested city centres, wrote E. H. Davenport, who gave an address in the Inner Temple, London’s legal quarter.

By the mid-1920s the volume of anti-tram letters in the press was running at about two to three times the number at the start of the decade. This was an orchestrated campaign. Most of the writers concealed their identity behind pseudonyms, such as ‘ratepayer’. Others gave false names or fake addresses.

The letters claimed that trams were old-fashioned and anachronisms. There was a smidgin of truth in this. Some tramways were poorly maintained. But most were not.

Today this type of propaganda campaign is common on social media, where it is known as astroturfing – a technique designed to give the impression of grassroots public opinion when in fact it is the product of hired hacks pushing corporate interests.

Ernest Harold Davenport was different. Not only did he give his real name and address but he later wrote an autobiography admitting that he organised astroturfing campaigns. In the mid-1920s he was freelancing for the oil company Shell, pushing the advantages of petrol.

Davenport was a maverick barrister, journalist and stockbroker. He wrote his anti-tram letters from a second-floor flat overlooking Temple Gardens, and within earshot of the Embankment trams, or ‘wheeled thunderstorms’ as he termed them.

And here the plot thickens. For Davenport’s flat, in this discreet gaslit-sanctum, was an MI5 safe house. His flatmate and long-standing best friend, Sidney Russell Cooke was also a barrister and stockbroker. He too had freelanced for Shell. Cooke was a semi-retired MI5 agent and his brother-in-law was MI5’s deputy director-general.

What role did the security services play in the demise of the tram? Both MI5 and MI6 had built up considerable expertise in black propaganda during the First World War. Cooke undoubtedly helped Davenport with some introductions and probably passed on some handy hints about mounting effective propaganda campaigns.

The Royal Commission Transport, which was set up in 1928, was much impressed by the number of articles in the press claiming that trams were obsolete and should be scrapped. It rejected the evidence of experts that the modern tram had a bright future. In 1931 the Royal Commission’s report recommended abolishing trams. And so the tram was doomed.

Want to read more about it? The full story is told in The Great Tramways Conspiracy, which will be published by Pen and Sword on 30th May.