In what is thought to be Britain's most fortified cannabis cafe, officers took around a quarter of an hour to gain entry to the building, on a slip road off Freshbrook Road, Lancing, during the raid during the evening of Wednesday, February 6.

The raid took place after two people, a man and a woman, were arrested for possession of cannabis after being spotted leaving the cafe.

But the heavy fortifications, which consist of metal poles surrounding the building, two "air lock" style steel doors and a high tech CCTV system, thwarted officers from getting inside the building quickly.

Adur Inspector James Asser said: "Officers saw a large plume of smoke emanating from the building on demanding entry and were delayed by some 15 minutes with the occupants failing to open the doors.

"This building is surrounded by steel poles on which sit tyres full of concrete, the windows are barred, the doors of which there are two comprising an air lock are constructed from steel with warnings of electrified wire present on the premises.

"Officers at the scene reported the smell of cannabis burning in the air while they waited for entry and on entering found a burner situated on the premises having been used prior to entry being gained."

No further arrests were made inside the building and no other cannabis was found.

It follows three previous raids on the building, one in July last year, where officers attempted to smash their way into the cafe using a battering ram.

Click here to see photographs from the raid.

During a second raid in October a tractor was used to pull out a window.

Click here to see a video of the raid.

The two people arrested this time received a caution.