13:50British Isles: A Natural HistoryEpisode 4: Islands ApartBBC One Duration: 48 minutes Thu 13th Mar 2014, 13:50 on BBC Two Northern IrelandAlan Titchmarsh travels Britain to discover why our islands are so diverse and extreme. When the Ice Age ended and the seas rose, we were cut off from mainland Europe.ContributorsProducer:Ian GrayPresenter:Alan TitchmarshGenresFactualHistoryFactualScience & NatureNature & EnvironmentSeriesBritish Isles: A Natural History Source: BBC Online