Sussex's last cannabis cafe was shut down after a dramatic siege involving more than 40 police officers.

The officers, including a dozen riot police, forced their way through two 6in-thick reinforced doors using welders and a battering ram.

About 30 people were marched outside once police had smashed their way into the heavily secured building yesterday. Acting Chief Inspector Stephen Eldridge said Operation Firebird had been a great success and a "substantial amount of cannabis has been seized".

He said: "We are very pleased.

"It took us a while but we expected it with those heavily fortified doors and we're still looking at forensics in the premises.

"We had to stop cutting through the door at one stage because there was someone behind it who refused us entry.

"We tried to negotiate entry but they still refused.

"Eventually they let us through the first door but nobody would let us through the second."

The raid on the cafe in Victoria Road, Worthing, began just before 1pm when police demanded to be let inside.

Smoke billowed from a chimney in what is believed to have been an attempt to burn the evidence before the police gained entry 20 minutes later.

Some of the cafe's customers gasped for air from the open windows on the other side of the building, covering their faces. Some called the fire services.

Two men and a woman were arrested for supplying cannabis. Another was arrested on an outstanding warrant unrelated to the operation.

Police said neighbours had reported about 200 people visited the cafe a day. They said complaints from the public and council leaders had become more frequent over the last three months and they had been planning yesterday's operation for six weeks.

Relieved residents from neighbouring businesses and properties gathered to watch the operation.

One man, who works nearby but did not want to be named, said: "We see all types of people going in there to get drugs.

"You name it, there are mums with children and people with walking sticks and crutches."

Another woman, who runs a business in the area, said: "They must have dozens of people in there an hour, and Friday night is always busier."

Most of the people inside, including a pregnant woman, were searched and released or cautioned.

One man, who had been inside when the police raided, claimed they had tried to co-operate with the police and let them in.

He said: "The police wouldn't let us open the door peacefully. They stormed us and we couldn't co-operate because we feared being beaten up."

He and others said the cafe was more like a "drop-in centre", with free internet access and sofas in a lounge area for people to relax.

Teresa Goldman, 30, who was searched before she was released, said cannabis should be legalised because it did no more damage than other substances and was less devastating than alcohol.

She said: "If I had teenage children I would prefer them to smoke cannabis than drink alcohol because, although it's legal, it causes more problems."

A 23-year-old woman, who visited the cafe six days a week, had just popped out from the cafe when the raid took place.

She agreed cannabis laws should be relaxed and said she has smoked cannabis for nine years and never drank alcohol or had gone on to try harder substances.

She uses cannabis for medical purposes.

West Sussex Fire and Rescue's Area Commander Neil Odin said firefighters were called to put out one fire in the building.

Fire inspectors were preparing to assess the building according to health and safety standards and could add weight to the police operation by issuing paperwork to close it down.

Police raided the cafe and two other similar operations in Worthing about 18 months ago. The other two have been closed down permanently.