"As always deferring the bridge"
Shows that the man has a preconceived fear and notion that crossing the bridge is bad- affecting his life
"The river nosed past, pliable, oil-skinned,wearing"-personification
River personified as rat, unpleasant, dirty,greasy.
"Something slobbered, curtly, close"-alliteration
•Alliteration of s's gives the rat a sneaky quality-emphasising the mans fear and how he finds them frightening.•Alliteration of c'c contrast to s and creates a harsh sound- heightens man's thoughts, creates feeling of immediacy. Gives impression that something going to happen.

"Dirty-keeled swans"- metaphor
Contrast to swans(usually regal, graceful)- sees them in jaundiced light. Drawn to the unattractive side of nature. Tinged.
"My throat sickened so quickly that I turned down the path in cold sweat"-enjambment
Between verses. Accentuates fear, speeds up rhythm, lack of punctuation, reflects speed of heartbeat
"I established a Dreaded bridgehead"-military reference
Taking a stand, incredibly(shows surprise by himself) also shows inner turmoil- reluctant yet determined.
"I turned to stare with deliberate thrilled care"-rhyming couplet
Only rhyming couplet- emphasises turning point.

Is going to and excited to face his phobia. Very significant change of tone- bravery. Highlights moment of change

"He trained on me. I stared him out"- military reference
Like face of enemy, battle between poet and rat(in his eyes) beating the rat but ultimately beating his fear. Moment of clarity.

Anecdote about possible origin of fear- childhood
Deeply embedded fear- since childhood.
"This terror, cold, wet furred, small clawed retreated up a pipe for sewage"-word choice
Deflates the rat back to true form- into right perspective. Realistic descriptions. Illuminated the mans feeling of triumph and "terror" is ironic as he does not correspond with description. Perhaps man feels silly for ever being afraid.
"Retreated"-word choice
Shows the man has overcome his phobia and has one the metaphorical battle
"Then I walked on and crossed the bridge"
Metaphorical and real bridge, man has overcome his fear and can move on with his life.

Advanced in his learning. Subtle confidence and pride. Triumphant tone.

Tone
•At start-disgusted, fear•Middle- determination, defiance•End- triumphant, pride also irony