Sorry about the video quality but the original file was made the exact date it happened so it was expected anyway
Credit to John Smith on the MHP Private Parts forum

Description on TVWhirl:
"Over Christmas 2002, the BBC started to air a load of new Wallace and Gromit short films. This mistake happened leading into one of them. The ident played as normal. It then stayed on screen as the programme music began playing in the background. A few seconds later, A caption was hastily thrown up. I managed to catch the end of it, with some of the music over the breakdown caption, then the announcer saying we can now return to Best Inventions... yes, completely missing the Wallace and Gromit segment that night! Although the looks may have changed several times, the BBC were still rocking those same breakdown tracks they'd had for years."