Aussie blokes backpacking through the UK are the most frequent sperm donors at London fertility clinics, according to new figures. Up to a third of donors in London are foreigners, and officials are hoping more Aussies will "lend a hand" since donor numbers in Britain are critically low. For 20 visits over several months, payments could add up to about £500 ($1200) and the enterprising backpackers use the money to support their travels. Spokesman Tim Mott of the Bridge Centre, one of the biggest clinics in London, says Britain needs more Aussie donors and their "winning spirit" and points out, "if we get enough Australian donors you could end up colonising the UK instead of the other way round." []