The Electric Telegraph Company (ETC) was a British telegraph company founded in 1846 by William Fothergill Cooke and John Ricardo. It was the world's first public telegraph company. 

Its headquarters was in Founders Court, Lothbury. This was the first company formed for the specific purpose of providing a telegraph service to the public. Up to this point telegraph lines had been laid mostly in conjunction with railway companies, and Cooke had been a leading figure in convincing them of its benefits. 

The equipment used was the Cooke and Wheatstone telegraph, an electrical telegraph developed a few years earlier in collaboration with Charles Wheatstone. 

However, these systems were all for the exclusive use of the railway company concerned, mostly for signalling purposes, until 1843 when Cooke extended the Great Western Railway's telegraph on to Slough at his own expense, at which point he acquired the right to open it to the public.

Railway telegraphy continued to be an important part of the company's business with expenditure on the railways peaking in 1847–48.

According to en.wikipedia