 After the death of owner Charles van Raalte in 1907 , his wife Florence stayed on Brownsea until 1925 . Mary Bonham @-@ Christie bought the island at an auction in 1927 . In 1932 , Bonham @-@ Christie allowed 500 Scouts to camp there to celebrate the Silver Jubilee of Scouting , but shortly afterwards she closed the island to the public and it became very overgrown . In 1934 , some Sea Scouts were camping on the island when a fire broke out . Mrs. Bonham @-@ Christie blamed the Sea Scouts , although the fire did not start where the Sea Scouts were camping . The fire engulfed most of the island , burning west to east . The eastern buildings were only saved by a subsequent change in wind direction . Although it was not known how the fire started , Scouts were not allowed to camp on the island again until after Bonham @-@ Christie 's death in 1961 . Her family becoming liable for inheritance tax on her estate , they put the island up for sale . Interested citizens who feared that the island would be bought by developers helped raise an endowment , and in 1962 the government allowed the National Trust to take over management of the island in lieu of the death duties . 
