In celebrating the trade union movement so soon after writing about the marriage of Prince Edward and Sophie Rhys-Jones, Professor Motion has made explicit his wish that the Poet Laureate be a people's poet as well as a celebrant of royal occasions.
This is the first time in its 131-year history that the TUC has been presented with its own Congress poem. Professor Motion will read the poem, entitled "In a Perfect World", to the TUC in Brighton next Tuesday, after speeches from the Prime Minister and Sir Herman Ouseley, who chairs the Commission for Racial Equality.
The 30-line verse describes a walk along the bank of the Thames in London from Richmond to Westminster, passing signs of Britain's industrial heritage. Written in the first person in a contemplative vein, the poem touches on issues of personal and collective freedom.
Professor Motion, appointed Poet Laureate in May after the death of Ted Hughes, said the work was "a public poem written in an intimate voice".
The TUC general secretary, John Monks, said: "We are honoured and delighted by the Laureate's acceptance of our invitation, which I know will be appreciated by the hundreds of trade unionists gathering in Brighton this weekend.
"The poem evokes liberty in a gently paced and beautifully understated way. This sunshine stroll both recaptures the legacy of our past and looks buoyantly to the future. It also reminds us that others around the world are still denied the basic freedoms we take for granted."
The verse has turned trade union leaders into literary critics. John Edmonds, general secretary of the GMB general union, described it as "earthy rather than lyrical;" something his members would identify with.
The poem was commissioned by the TUC, but no fee is being paid to the Laureate.
By Andrew Motion
I was walking the Thames Path from Richmond
to Westminster, just because I was free
to do so, just for the pleasure of light
filling my head, just for the breeze like a hand
tap-tap-tap tapping the small of my back,
just for the slow and steady breath of dust
fanning on flints, on cobbles, on squared-off
slab-stones - dust which was marking the time
it takes for a thing to be born, to die,
then to be born again. The puzzled brow
of Parliament filled the distance, ducking
and diving as long parades of tree-clouds
or skinny-ribbed office blocks worked their way
in between. The mouth of the Wandle stuck
its sick tongue out and went. The smoke-scarred walls
of a disused warehouse offered on close
inspection a locked-away world of rust
and sand flecks and slate all hoarding the sun.
That's right: I was walking the Thames Path east
as though I was water myself - each twist
and turn bringing me out on the level,
leading me hither through brick-chinks
into the hush of my clarified head,
into the chamber where one voice speaking
its mind could fathom what liberty means,
and catch the echo of others which ring
round the rim of the world. Catch and hold.
The buttery sun kept casting its light
on everything equally. The soft breeze
did as it always did, and ushered me on.