For 51 years Times readers have been looking hopefully in these pages for the string of digits that could make them rich. And if your Premium Bond number does come up, you have Ernie to thank. By injecting a bit of excitement into the business of saving, Ernie, the machine that generates the winning numbers, became a celebrity, and now the original machine has gone on permanent display at the Science Museum in London.

It is a glorious slab of 1950s technology, all angular metal protruberances, rows of transistors, knobs and dials. Yet when Ernie came into service in 1957, The Times was not impressed, the archive reveals. The machine was described as “merely a grey metal cabinet about 10ft long and 7ft high”.

This hardly did justice to what was then a very advanced piece of hardware. The Electric Random Number Indicator Equipment (to give it its full name) was a direct descendant of Colossus, the world’s first digital computer, made by British code-breakers during the war. Ernie is not strictly a computer, as it cannot be programmed, but rather a true random-number generator. Although the algorithms used by computer programs approach randomness, they are never entirely without patterns — or free from the possibility of manipulation. By contrast, Ernie passed an electric current through neon gas, producing excited electrons that hit a metal plate in a properly random physical event.

Each chunky number generator had heavy shock absorbers to prevent vibrations influencing the result and, to make doubly sure, the output of one generator was subtracted from the output of another to produce each individual digit of the winning numbers. These were then checked against a bank of all issued bond numbers hardwired into Ernie’s back, before issuing forth from the teleprinter.

Times Archive, 1957: Ernie's first draw

Ernie is no more exciting to look at than 'a closed bookcase with teleprinter attachment'

• The importance of being Ernie

• 'Ernie fulfilled expectations'

As a spectacle, it lacked the pizzazz of today’s lottery draws. The Times described the first draw, in Lytham St Anne’s: “Surrounded by several hundred civil servants, ‘Ernie’ in his humdrum northern shrine affords the only touch of glamour in the whole affair.” Even Ernest Marples, the Postmaster General, who kicked off the first draw, described Ernie as looking like “a closed bookcase with teleprinter attachment”.

Premium Bonds had been launched by Harold Macmillan, the Chancellor, as a way to encourage Britain to save more, but were initially controversial. The Shadow Chancellor, Harold Wilson, denounced the scheme as “a squalid little raffle”, and the Archbishop of Canterbury went even farther, calling it “a cold, solitary, mechanical, uncompanionable inhuman activity”.

But Ernie soon endeared himself to the nation. On display next to the machine at the Science Museum are some of the cards sent to him by those whose numbers came up, with messages like “thank you for being a life-changing experience”.

Ernie 1 has long since been retired, and the draw is now performed by Ernie 4. The original produced a creditable 2,000 numbers an hour, but the modern version manages a million in the same time.

In the museum’s computing gallery, Ernie is now on show without the heavy security doors that so disappointed the early Times correspondent, and is a handsome sight for lovers of Fifties aesthetics and processing buffs alike.

In a space that already features some of the early Babbage engines — not to mention the pickled brain of Babbage himself — Ernie is a welcome addition.