Hampshire and Isle of Wight Police and Crime Commissioner Donna Jones backs calls for the Online Safety Bill to go further to safeguard children.
Her comments come after Conservative MPs have put pressure on the government to ensure the legislation holds social media bosses to account for harmful content.
She said: “Protecting children should be the number one priority for any government.
“Harmful online content is affecting children every day, from encouraging suicide to putting them at risk of sexual abuse.
“The internet can be a dangerous place for children and fining big tech companies is not enough.
“It must go further with criminal prosecution leading to prison for those found knowingly allowing harmful content to be available.
“I fully support a criminal prosecution and up to two years in prison for those who fail to safeguard the most vulnerable.
“This is an opportunity to protect a generation of children, now and in the future.”
PCC Donna Jones has contributed to the draft legislation in her role as the Joint APCC Lead for Victims.
She has previously put forward her support to increase the list of priority offences that relate to harmful material, to be removed by platforms.
As a result, more offences including revenge porn, hate crime, the promotion or facilitation of suicide and sexual exploitation, were added to the list of priority offences which means that material relevant to these offences must be removed by platforms.
Ms Jones added: “PCCs want their communities to feel safe on- and offline and we will continue to work with partners and the government to ensure this happens.”