It has emerged that the Conservatives may be responsible for further delays in plans for postal voting for the European and local elections.

In April the Tories sent out information packs with application forms to four million voters outside the all-postal ballot areas asking whether they wished to vote by post.

The forms were designed by the party and asked the applicant to fill them in and return them to a Tory party mailing centre.

Returning officers now say that in the past few days they have received thousands of requests for postal ballot papers from local Conservative Party associations.

One official claimed that Tory headquarters had stored the papers and failed to send them on to the local party associations.

"This has created a considerable problem," one official said. "We are receiving hundreds of new forms every day. We now have to print thousands of new envelopes and get them out in time."

A spokeswoman said that Electoral Commission chairman Sam Younger had warned the Tories that they should have asked voters to send their application forms directly to a local council rather than to a central mailing centre.