A British boy is set to return home after spending five months in a US prison after being arrested for being high on meth, police said.

The 13-year-old boy, who cannot be named for legal reasons, was found to be high on methamphetamine on his way to his school on Tuesday, police in Portland, Oregon, said in a statement.

Police said the boy was apprehended by officers and taken to a police station where he was treated for hypothermia.

Officers found him slumped on the floor and the teen’s body was wrapped in blankets.

The boy was later taken to hospital where he died, police added.

The boy was taken to the state’s juvenile justice facility where he remained until his death.

He will be placed in foster care pending his case, the statement said.

Drug-related deaths have risen in the US in recent years, with the number of people arrested for drug offences quadrupled from 2009 to 2016, according to a Washington Post analysis.

The Washington Post analysed data from the US Justice Department’s National Institute on Drug Abuse and the Drug Enforcement Administration and found that drug-related homicides rose from 13 in 2014 to 35 in 2016, a rise of 70%.

“This is the highest year-over-year increase we’ve seen,” said Mark Kleiman, the Post’s drug policy analyst.

“The rise has coincided with the growth of states that have loosened restrictions on the drug trade and a dramatic rise in the use of marijuana.

This trend has been mirrored across the US, with many states allowing adults to use marijuana and decriminalisation, while others have introduced new laws to deal with marijuana, such as the possession of small amounts of marijuana for personal use.

The United States has a large population of people aged 12 to 20.