London - Fans of the pop group Take That have complained after facing major problems buying tickets to see Robbie Williams tour with the group for the first time in 16 years.
Unprecedented demand overwhelmed official ticket agencies, so many fans were to unable to access their websites or get through on the phone, the BBC reported on Friday.
"Ticket buying is a nightmare!" one fan named Louise wrote. "You would think there would be something in place to prevent the nightmare of crashing sites."
The websites of official agencies including Ticketmaster, See Tickets, Ticketline and The Ticket Factory all buckled under the strain as the tickets went on sale at 0900 BST (0800 GMT).
Ticketmaster said the demand was at least double that seen when tickets for Michael Jackson's planned comeback concerts at the O2 arena in London went on sale last spring.
Hundreds of fans have also been queuing at venue box offices, while BT said the national phone network had received between three and four times the normal number of calls.
A Take That spokesperson urged fans to be patient.
"Massive demand this morning has caused phone lines and websites to jam as ticket agents have struggled to cope with the number of people trying to buy Take That tickets," the band said in a statement.
"However all ticket agents are confident they will be able to process all enquiries so are asking fans to keep trying."
The group has announced dates in Sunderland, Manchester, Cardiff, Dublin, Glasgow, Birmingham and London in May, June and July. They will also take the show across Europe.
Williams rejoined the group this summer. Their new album, Progress, will be released next month.
- Reporting by Paul Casciato, editing by Patricia Reaney