This is the only edition of the twelfth series where the ratings cannot be traced, as the show wasn't listed in the Top 100 chart for that week. However, rather than being a massive plummet in the ratings, this would possibly appear to be an error in the way BARB ratings were reported.
The episode was bookended by Episode #8.147 (1988) and the highlights show "21 Years of The Two Ronnies". The audience for Wogan was given as an average of all three episodes for the week, but was calculated as 7.8 million/54th place. Meanwhile, the audience for The Two Ronnies was 10 million/30th place.
The 100th-rated programme for the week was Episode #2.15 (1988) with 4.5 million. If Blankety Blank didn't make the Top 100 for the week, it would have to be assumed that the BBC1 audience not only grew by at least 5.6 million after it finished, but also that the ratings were over 4 million lower than the rest of the Series 12 average.
The episode was bookended by Episode #8.147 (1988) and the highlights show "21 Years of The Two Ronnies". The audience for Wogan was given as an average of all three episodes for the week, but was calculated as 7.8 million/54th place. Meanwhile, the audience for The Two Ronnies was 10 million/30th place.
The 100th-rated programme for the week was Episode #2.15 (1988) with 4.5 million. If Blankety Blank didn't make the Top 100 for the week, it would have to be assumed that the BBC1 audience not only grew by at least 5.6 million after it finished, but also that the ratings were over 4 million lower than the rest of the Series 12 average.
It's clear from the reactions of the panel, audience and contestants that Stan Boardman writes down at least one rude answer that produces hysterics, but isn't shown onscreen.