<P> Their overarching international association, The Rats of Tobruk Association, is partly responsible for the erection of numerous monuments in Australia and the UK and involvement with official memorial services . The association also organised with the Royal Mint of Australia the striking of a 50 - year anniversary medallion in 1991 . </P> <P> The association's insignia shows the elements of a large uppercase letter' T', for Tobruk, a long - tailed desert rat, and a crown . The crown depicted is variously the Tudor Crown or St Edward's Crown (since 1953), representing allegiance to the Australian Sovereign, or a crown mimicking Tobruk's official pre-war city flag which was liberated from the city's hall during the siege . </P> <P> In April 2007, the Victorian contingent of the Rats of Tobruk Association concluded that it could no longer afford the upkeep of Tobruk House, the inner - city Melbourne meeting hall that had been purchased by the Association in the 1950s . Back then, the Victorian Association had 1,800 members . By 2007, there were just 80 left, all aged in their 80s and 90s, who decided to sell the hall . From the sale, they hoped to raise up to A $1.5 million to be used for research at Royal Children's Hospital, Melbourne, where a neuroscience ward, the Rats of Tobruk Ward, had already been named after them . Bill Gibbons, who made his wealth out of trucking, went well beyond the expected price to outbid a Sydney developer for A $1.73 million . As reported by The Age, "in an act that stunned the old diggers, Mr Gibbons...then told the veterans they could keep the hall as long as they wanted ." </P> <Ul> <Li> Charles Chauvel directed a 1944 movie titled The Rats of Tobruk, starring Peter Finch and Chips Rafferty, see IMDB . </Li> </Ul>

Why were they called the rats of tobruk