Update: Lincolnshire Police confirmed on Monday evening that Calum has been found safe and well and returned home.
A 15-year-old boy from Grantham has been missing since Saturday morning. Police are concerned for his welfare.
Calum Copus left his home in Grantham about 3am on Saturday, May 18 and has not been seen since.
He was wearing black clothing and carrying a black rucksack.
He was also riding a small blue bike, police said.
Anyone who saw Calum anytime on Saturday, or has information regarding his whereabouts, should contact Lincolnshire Police on 101.