Conservative Party members who have defected to the anti-European UK Independence Party could influence the Tory leadership contest, it was claimed yesterday.
Tory Party members are normally given a three-month period of grace to renew their membership when it runs out, after which it is considered to have lapsed.
A UKIP organiser said yesterday he knew of many of his members who had left the Conservative Party but were still listed as members because of the three-month period of grace.
The issue was just one of a string of anomalies about the Tory leadership poll discovered by the BBC's Today radio programme yesterday.
The programme spoke to a woman, who did not give her name, who said she had received ballot papers although she was not a Conservative Party member.
"I can only think that the Conservative Party have got inaccurate records," she said.
However, Tory Party vice-chairman Mr Stephen Norris said the cases where anomalies had appeared were isolated and would in the end make little difference in the contest.
"The reality is I don't think any of this is going to have the slightest impact on the outcome," he said.
"The overwhelming number of members have got their ballot papers and actually what is interesting, I think, is that the vast majority of them will return them within 72 hours."