Dry batteries when near the end of their life produced crackles in the radio. This advert points out the advantage of the rechargeable lead-acid battery for HT. It ignores the health risk associated with the high current the battery can deliver.
Some radio users attached a large value capacitor across the dry HT battery to suppress the crackles.
In 1925, the British government asked Lord Weir, a Glaswegian industrialist, to solve the problem of Britain's inefficient and fragmented electricity supply industry. Some places with AC mains, others with DC and some without electricity.
The 1926 Act created the Central Electricity Board, which set up the UK's first synchronised, nationwide AC grid, running at 132 kV, 50 Hz. The grid began operating in 1933 as a series of regional links with auxiliary interconnections for emergency use. Following the unauthorised but successful short term paralleling of all regional grids by the night-time engineers on 29 October 1937, by 1938 the grid was operating as a national system.