The poem you are looking for is titled My Policeman by Rose Fyleman. A
quick search using the lines you provided immediately showed the
answer. Google Web search showed only one link which when clicked will
show a "The page cannot be found" error page. Lucky for us there's the
Google Cache which saved the day -- thank God for that. :-)
Here's the complete poem:
By Rose Fyleman
He is always standing there
At the corner of the Square;
He is very big and fine
And his silver buttons shine.
All the carts and taxis do
Everything he tells them to,
And the little errand boys
When they pass him make no noise.
Though I seem so very small
I am not afraid at all;
He and I are friends, you see,
And he always smiles at me.
Once I wasn't very good
Rather near to where he stood,
But he never said a word
Though I'm sure he must have heard.
Nurse has a policeman too
(Hers has brown eyes, mine has blue),
Hers is sometimes on a horse,
But I like mine best of course.
You'll find other classic children's poems from the source:
Children's Poems - Tall Folks, Short Folks
"he is always standing there" "at the corner of the square" "he is
very big and fine" - in Google Web search
I hope this helps you. Should you have any comments/questions, please
feel free to post your clarification before rating this and I'll
attend to you as soon as possible. Thanks for asking.