A concert in Birmingham to celebrate the arrival of the Olympic torch relay in the city has been overshadowed by a blunder over ticket distribution.
There were 20,000 free tickets for the Cannon Hill Park event but Ticketmaster mistakenly emailed everyone who applied to say they had been successful.
A new ballot for tickets for the gig on 30 June will now have to take place.
It is the latest blunder in a series of problems for Ticketmaster, which is in charge of selling London 2012 tickets.
In January the Ticketmaster website for the resale of unwanted Olympic tickets crashed on the day it was launched.
The site was down for 11 days before it was up and running again.
Speaking about the Birmingham event, a Ticketmaster spokesman told the BBC: "Due to a data processing error, Ticketmaster incorrectly advised all customers who had entered the ballot for tickets to the London 2012 Olympic torch relay special city celebration in Birmingham that they were winners in the ballot.
"All customers who originally entered the ballot have been informed of the error and that all tickets previously claimed have been invalidated.
"In the interests of fairness to all applicants the ballot has now been declared void."
Boy band The Wanted are playing at the concert, which ends day 43 of the relay running from Derby to Birmingham.
The 70-day relay gets under way from Land's End on Saturday.