Football fans who abuse players or fellow supporters online have been warned they could face prosecution, as lawyers and police unveiled a new policy for tackling hooliganism.
Sports prosecutor Nick Hawkins said criminal abuse inside as well as outside sports grounds would be dealt with in the run-up to England World Cup qualifiers in the autumn.
He said: "It's not just criminality in the stands that will be taken on. Our legal guidance on communications sent by social media clearly sets out how we will approach the abuse of players or fellow supporters online and I'm glad to say we have the full support of the Football Association and the Professional Footballers' Association in this field."
New guidance issued by the Crown Prosecution Service (CPS) earlier this year said that communications that included threats of violence or damage to property, specifically targeted individuals, or that may breach a court order should be "prosecuted robustly" if there was enough evidence for a realistic prospect of conviction.
Others that were "grossly offensive, indecent, obscene or false" may not reach the criminal threshold.
The new guidance comes after a series of high-profile cases involving Twitter, including threats made against feminist campaigner Caroline Criado-Perez and MP Stella Creasy, as well as several female journalists.
The policy, issued by the CPS and the Association of Chief Police Officers, also deals specifically with homophobic chanting.
It says: "As well as tackling violence, disorder and criminal damage we will deal robustly with offences of racist and homophobic and discriminatory chanting and abuse and other types of hate crime."
Alice Ashworth, from charity Stonewall, said that gay fans were put off going to matches because of homophobic chanting.
She said: "We welcome the fact that the new policy on football-related offences addresses homophobic chanting for the first time."