(ed: sung - very roughly - to the tune of Scotland the Brave:)

Fart, fart the beans are calling
Must be the ones I ate this morning
Off to the loo to do a phhhpt! in the loo

If there is no toilet paper
Use your finger as a scraper
Off to the loo to do a phhhpt! in the loo.

Alternate version sent in by 'shooeymooey')

Fart, fart the beans are calling,
must be the ones ah ate this mornin,
went tae the toilet done a phhhpt! on the floor,
sorry maw I didn ae mean it,
gie me a bob an I'l help ye clean it,
thats what ye get for eatin heinz baked beans