Tory membership has halved since David Cameron became leader, with just 134,000 constituency members remaining with the party.
The figures, which have finally been revealed by the Conservative central office following a sustained campaign by ConservativeHome, lays open the crisis in Conservative membership rates and highlights why the party has been so susceptible to a Ukip threat from the right.
"The halving of Conservative party membership under David Cameron is a damning indictment of Cameron’s out of touch and weak leadership," vice Labour chair Michael Dugher said.
"The Tories are deserting Cameron in their droves.
"Under Cameron, the Tories are becoming an endangered species. They are getting fewer and fewer in number by the day."
In 2005, 253,600 members voted in the leadership contest between David Cameron and David Davis.
The actual membership at that time was probably slightly higher, but even under these figures it appears Conservative membership has halved under Cameron's leadership.
The party puts its membership at 174,000, because it includes 'friends, non-member donors and others in the numbers.