Prosecutors said Cashford was chased and hit with rocks and a bottle before he was found lying face down in the mud.
“This was a carefully pre-planned deliberate and violent attack on someone… who could not defend himself,” Natalie Smith, from the Crown Prosecution Service (CPS), said.
“Despite his best attempts to flee, he was relentlessly pursued and attacked, even when witnesses reported he was lying on the ground.”
Cashford, an electrician, had more than 30 external injuries on his body, the jury heard.
During the sentencing at the Old Bailey, his parents said they were “crushed” by what had happened to their “kind, friendly and compassionate” son.
They called his killing “cruel, unnecessary and pointless”.