Country singer could face up to six months in prison after police discovered six ounces of marijuana on his tour bus

Country star Willie Nelson, a long-time activist for the legalisation of marijuana, has been arrested for cannabis possession. The singer could spend up to six months in prison, with a Texas sheriff promising "to make him cook and clean".

"We treat him like anybody else," sheriff Arvin West told the El Paso Times. Nelson, 77, was en route from California to Austin, Texas, where he owns a ranch. Cruising the highways on a bus called the Honeysuckle Rose III, Nelson came to a border control stop at 9am on Friday morning. Even at that early hour a suspicious smell allegedly wafted from inside the vehicle. Agents searched the bus, discovering six ounces (170g) of marijuana. Nelson reportedly admitted the drugs were his and was taken to Hudspeth county jail.

"He said he feels great," harmonica player Mickey Raphael told Rolling Stone. But although Nelson posted $2,500 (£1,600) bail, sheriffs say he may return for a longer stay behind bars. "He could get 180 days in county jail," West said. "If he does, I'm going to make him cook and clean."

In 2006, Nelson narrowly avoided jail after being arrested for cannabis possession in Louisiana. Officers seized more than 20 ounces (567g) of marijuana and 3 ounces (85g) of magic mushrooms; he was later sentenced to six months' probation. "Both bus drivers were over 50 years old," Nelson explained at the time. "The other guys were 60 years old. My sister is 75, I'm 73, so it's like they busted an old folks' home." In January, six members of Nelson's band were charged with possession of moonshine and marijuana in North Carolina.

Nelson, famous for singing songs such as Always On My Mind and To All the Girls I've Loved Before, is a supporter of marijuana legalisation. He sits on the advisory board for the National Organization for the Reform of Marijuana Laws and has organised fundraisers for the group. "It's a matter of time," he said in 2008, "a matter of education, a matter of people finding out what cannabis, marijuana is for, why it grows out of the ground and why it's prescribed as one of the greatest stress medicines on the planet."