Scientists are trying to keep out alien species of plants and animals from Antarctica, worried that they might disrupt the fragile environment.

The picture on the left shows one of the few bits of Antarctic plant life I saw on a 2-day trip to a region 250 km (155 miles) from the sea: a few inconspicuous dark bits of lichen or moss growing amid snow in a rock cranny.

Even small patches of life sometimes turn out to be centuries old and have survived storms, winter darkness and temperatures that sometimes plunge to about -40 Celsius. 

To keep out competitors, even the roses in Norway’s Troll Station are artificial under rules preventing introduction of any living thing — even though roses are unlikely to grow around here.

Before travelling, by Hercules transport plane from South Africa, I shook off my clothes and rucksack — which had come from Norway where temperatures are also very cold — to get rid of any spores or seeds. Scientists say that seeds often cling to your clothes.

At the Troll base the possible technical violation I saw was that they had brought grapes from South Africa — as with roses, the chances of vines sprouting in Antarctica now are about as remote as finding an alien clambering out of a spaceship.

Some workers at the base also said they’d like to have an enclosed greenhouse to experiment with sowing seeds and see if they can grow vegetables to brighten up a diet that is mainly of frozen food …. Should they be allowed to? Or should the rules be enforced fully to protect Antarctica as a last great wilderness?