When Dreadnought made the pre-dreadnought era visibly obsolete

When did it become apparent that the pre-dreadnought battleship era was ending?

The warning came earlier, but Dreadnought reaching the slipway made the break with the old standard unmistakable.

Naval observers heard that Britain was preparing an unusually powerful battleship before they could see the ship itself. The decisive threshold came when Dreadnought reached the slipway and the new standard became a physical construction programme rather than a rumor. Existing pre-dreadnoughts did not cease to function, but they were now measured against a radically different arrangement of speed and heavy guns. The answer captures how technological obsolescence can become strategically real before the older equipment leaves service.