In a statement released by Wiltshire Police, Det Sgt Bailey said the experience had been ”completely surreal” and that “life would never be the same again”.
“There are really no words to explain how I feel right now,” he added.
Det Sgt Bailey said he had been “overwhelmed” by the support he had received.
He was taken to Salisbury District Hospital after responding to the attack on former Russian double agent Sergei Skripal, 66, and his 33-year-old daughter Yulia on March 4.
His wife, Sarah, said in a statement: ”Nick doesn’t like the term hero, but he has always been a hero to me and our children.”
DS Bailey insisted “I am just a normal person with a normal life”, but added: “I recognise that ‘normal’ life for me will probably never be the same – and Sarah and I now need to focus on finding a new normal for us and for our children.”
Cara Charles-Barks, chief executive of Salisbury NHS Foundation Trust, confirmed the injured officer left hospital earlier on Thursday, nearly three weeks after the attack on Mr Skripal and his daughter.
She said the Skripals remain in hospital in a critical but stable condition.
Earlier, a court was told Mr Skripal and his daughter may have suffered life-long brain damage as a result of the military-grade nerve agent they ingested.
The pair remain in intensive care under heavy sedation, Mr Justice Williams told the Court of Protection.
“The precise effect of their exposure on their long term health remains unclear but medical tests indicate that their mental capacity might be compromised to an unknown and so far unascertained degree,” the judge said.
“At present both Mr and Ms Skripal are critical but stable; it is not inconceivable that their condition could rapidly deteriorate.”
A consultant treating the victims as Salisbury District Hospital said Mr Skripal was unable to communicate in any way, but his daughter was unable to communicate in any "meaningful way".
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