The star has also cancelled her own ITV music special, after being forced to cut her acceptance speech for winning Best British Album short last Tuesday.
The Daily Star Sunday reports that instead Adele will be making an appearance on The Voice UK on BBC One next month.
“Adele was embarrassed by the way she was treated in front of millions of viewers by ITV," an insider told the newspaper.
“By turning down a music special with the network and also appearing on its main rival’s music show she is giving them the ultimate one-fingered salute."
They added: “Adele is the biggest British name in music in the world at the moment and her refusal to work with ITV will hit them hard.”
Adele's album, 21, shot back to number one this week after the BRITs, having sold over 4 million copies in the past year.