In the first half of the song, the “Uncle Albert” part, there are spoken lyrics:
We’re so sorry, uncle albert,
But we haven’t done a bloody thing all day.
We’re so sorry, uncle albert,
But the kettle’s on the boil
And we’re so eas’ly called away.
He did the voice in a concert back in the day. He cupped his hands around the microphone when he did it. He only had to do the first line, the audience finished that part for him.