When did 'Can a parrot eat a carrot' by spike milligan written?

The poem appears in the book "Silly Verse for Kids" by Spike Milligan which was first published in 1968, although some of the poems were previously published as early as 1959.

Can a parrot

Eat a carrot

Standing on his head?

If I did that my mum would send me

Straight upstairs to bed.

- Spike Milligan