A former head teacher of an infant school who was jailed for possessing indecent images has been banned from the profession for life.
Daniel Chapman, of Chelmsford, Essex, also discussed child sexual fantasies with other men.
Now aged 33 and known as Alexander Martin, he admitted 12 offences and was.
A professional conduct panel said the offences were "very disturbing".
Martin was suspended and eventually sacked from his role at Hilltop Infant School in Wickford, Essex, following his arrest in May 2019.
No children from the school were involved in his offending.
Judge Patricia Lynch QC, who sentenced Martin in 2019, said he had sent "depraved, revolting and broadly sadistic" messages to four men.
Dozens of indecent images and two videos were found on his phone.
'Risk of repetition'
He admitted 12 charges on the first day of his trial, including possessing indecent images and publishing indecent articles on messenger sites, and was put on the sex offenders register for 10 years.
As part of his teaching role he had taken a course about safeguarding children from abuse online and had expert knowledge of the effects of abuse.
The Teaching Regulation Agency panel said as a convicted paedophile, Martin's actions were "fundamentally incompatible with his being an educator".
"This was conduct of the most serious nature," it added, noting that the offences "had a detrimental impact on the school, its pupils and the local community".
As head teacher, he was a role model in a leadership position of trust and responsibility and "had fallen very far short of the standards expected of him in that regard," the panel said.
His lack of insight - having initially contested aspects of the charges - "means there is some risk of repetition", it added.
A decision-maker acting on behalf of education secretary Gavin Williamson prohibited him from teaching indefinitely and ruled he could not apply to have his eligibility restored.