Through most of the 19th century the Isles of Scilly were a week's news behind London. The mail packet boats from Penzance ran when the weather allowed and often did not. In the late 1860s a Mr Buxton, a local advocate, lobbied the Post Office to install a submarine telegraph. The Post Office refused. So a private consortium took it on: the Scilly Islands Telegraph Company, with the solicitors Ashurst, Morris and Company of Old Jewry in London handling the contracts, and the engineering subcontracted to a Mr Fenwick of Gateshead. Fenwick was already a veteran - he had been responsible for the very first submarine cable between Dover and Calais, completed in September 1851. He knew what was required. The Scilly job, by comparison, was straightforward.

The cable itself was a marvel of Victorian rope-making and electrical engineering. Three copper wires sheathed in India rubber sat at the core, manufactured by the Silvertown Company. Around them ran six strands of Manilla hemp, each strand encasing a galvanised iron wire for tensile strength. The whole bundle weighed 17 long hundredweight per mile - over three quarters of a ton - and could take a three-and-a-half-ton breaking strain. The shore ends, the first mile and a half on each side, were sheathed in additional galvanised wire to resist chafing on rocks, increasing their weight to four tons per mile. On 22 September 1869 the steamer Resolute from Newcastle arrived at Penzance carrying the entire 30.5 miles in one continuous spool, the longest unspliced cable yet manufactured.

On Saturday 25 September 1869 the steamer Fusilier, under Captain Jacques, anchored off Mill Bay on the Cornish coast, a small cove about a mile and a half south of Land's End. The crew fired rockets carrying lines ashore; the lines were used to haul the heavy cable end onto the beach at Zawn Reeth, where it was buried and connected. Then the Fusilier turned west and paid out the cable behind her, mile after mile, over the open sea to the Isles of Scilly. By Sunday 26 September the shore end reached Deep Point, on the eastern coast of St Mary's beneath the high lands of Normandy. A 20-word message from Penzance to Scilly cost 2s 6d - several days' wages for an islander - and required the recipient to come up to the new telegraph office to collect it.

The cable broke in mid-1870 and had to be repaired. A second cable was laid the same year, this one routed through the wider postal telegraph system so that messages could go to or from any Post Office in the United Kingdom for an extra shilling. A branch to Tresco was opened on 28 June 1870. The service failed again in 1876; the Scilly company could not afford to repair it; eventually the Post Office bought the whole operation in 1879 and reduced the message tariff to one shilling for twenty words. The tower on the hill - the telegraph office and lookout that gave the settlement its name - became a coastguard station, which closed only in 2017. Around the tower the land is now an unhurried Edwardian golf course, the only one in Scilly, with nine holes and two tees each, founded in 1904. The old telegraph wires are gone. The submarine cables that connect the islands to the mainland today still come ashore at Porthcurno on the Cornish side - a different route, a different century, the same hill watching.