The European and local elections may be in jeopardy because some postal ballot papers may not reach voters until four days before the June 10 poll.

Royal Mail said yesterday that it could not guarantee that postal ballots sent back on June 8 would reach the counting stations by the deadline of 10pm on June 10.

"It is extraordinary that the government is prepared to risk the possibility of denying people their democratic right to vote and a skewed result," said Bernard Jenkin, Tory spokesman for the regions.