On the city's police website, spokesman Jonah Spangenthal-Lee said: "The department's going to give you a generous grace period to help you adjust to this brave, new, and maybe kinda stoned world we live in."

He added: "The police department believes that, under state law, you may responsibly get baked, order some pizzas and enjoy a Lord of the Rings marathon in the privacy of your own home, if you want to."

The department also posted a picture of actor Jeff Bridges as the cannabis-smoking character "The Dude" from the comedy film "The Big Lebowski".

Encouraging indoor cannabis smoking, it carried the caption: "The Dude abides, and says, 'take it inside!"

Washington and Colorado became the first two states decriminalise and regulate the possession of cannabis in ballots held alongside the US presidential election on Nov 6. The Colorado law takes effect on Jan 5.

In Washington it is now legal for adults over the age of 21 to possess an ounce of the drug, or up to 16 ounces of cannabis-infused goods like brownies or cookies, or up to 72 ounces in liquid form.

Growers and processors of cannabis will be regulated and the drug will be sold in licensed shops.

It will be subject to a 25 per cent tax at each stage of that process. The move is expected to bring hundreds of millions of dollars in tax revenue for spending in areas including schools and health care. The establishment of the regulation and tax system will take another year.

However, with cannabis still illegal under United States law, through the Controlled Substances Act, Washington could face a crackdown by federal agents from the FBI and Drug Enforcement Agency.

The drug remains banned from federal property in the state, including military bases and national parks.

Washington's stance comes in the wake of an already escalating conflict between the federal government and states over the burgeoning medical cannabis industry.

The US Attorney's Office has previously launched crackdowns in states, including California, where dispensaries selling cannabis for medical use have proliferated. It has taken legal action to shut down many it believes were operating illegally.

On Wednesday the federal US Attorney's Office in Seattle said that, effectively, nothing had changed. It said: "The department's responsibility to enforce the Controlled Substances Act remains unchanged. Neither states nor the executive branch can nullify a statute passed by Congress."

The US Justice Department has yet to announce whether it will sue in the courts to try to block regulation and taxation of the cannabis industry in Washington and Colorado, which would set up a legal showdown over states' rights.

At the Space Needle, the mostly middle-aged group of cannabis smokers listened to reggae music from loudspeakers.

They included Mike Momany, 61, who said he intended to form a Washington State Cannabis Tourism Association.

Another smoker, calling himself "Professor Gizmo," 50, said: "Victory for hemp. If our forefathers could see us now."

http://www.telegraph.co.uk/news/worldnews/northamerica/usa/9728034/...