It is based on the piece Asterix est là composed by Vladimir Cosma, which was used in the previous film Asterix - Victory over Caesar by Plastic Bertrand, but is slower in this version and has new English text. The theme song The Lookout is out was recorded by the British band Cook da Books. It was released in theaters in France on December 3, 1986, in the Federal Republic of Germany on Maand in the GDR on March 18, 1988. Back at home in Gaul, they finally learn from Miraculix that the oriental herbs are tea leaves. They drink from it and feel so inspired that they actually manage to defeat the approaching Romans. In dire need, Asterix had the idea of adding the Phoenician herbs to the hot water of the British and giving the drink to the villagers as a magic potion. Asterix, Obelix and Teefax bring the barrel back, but shortly afterwards it is destroyed by the Romans, with which the magic potion is lost. The thief Machfax manages to steal some barrels, including the one with the magic potion. The Romans want to prevent this by all means and have all the city's wine barrels confiscated. The Centurion Stratocumulus has since learned that the Gauls are about to bring a keg of magic potion into the British village and reports it to Prefect Motus. They travel on to Londinium, where they visit the Gaul Gaulix, the owner of the tavern "La Gauloise Amphore" ("To the Gallic Amphore"). In Britain they stop at the restaurant “Le rieur sanglier” (“To the laughing wild boar”), where they get to know the British eating and drinking habits, such as lukewarm cervisia and boiled wild boar in peppermint sauce. Obelix sinks the pirate ship and saves the Phoenicians, who give them a sack of fine herbs from the Orient as a thank you. During the crossing in their boat, they meet pirates who are about to raid the galley of a Phoenician trader.
Since Teefax cannot transport the barrel back to Britain alone, Asterix and Obelix are to accompany him. Upon his arrival, Miraculix immediately brews him a barrel of his magic potion. So Teefax sets out on a journey to the Gauls. Here is Teefax the idea of help from the Gallic village of his cousin Asterix from Aremorica request, known for his potion and the successful resistance against the Romans. There Sebigbos nervously awaits the next attack by the Romans, who have requested reinforcements. In this way they succeed in subjugating Britain in a very short time - with the exception of a small village that is still resisting.
Prefect Motus is at a loss and reports to Caesar, who now decides that the Romans should start all attacks at five o'clock and strike more on the weekends. There the British put up bitter resistance, but ended the fighting with the Romans at five o'clock sharp in the afternoon to drink hot water. The Romans under Julius Caesar intend to conquer Britain and transfer their troops to the island by ship.