September is the month when Fair Isle begins to batten down for the winter. Twice this month, on the 11th and 25th, a sturdy little boat called the Good Shepherd IV will chug out of the island's harbour for the four and a half hour journey to Lerwick in the Shetland Islands. And then no more trips to Lerwick until spring 2009.

Tidal islands
There are islands which never lose their island status. And then there are islands which come and go with every tide. Such fragments of land, which are only proper islands at low tide, are called drying islands or tidal islands. We look at some ...