Take That's concert promoter has apologised after fans were forced to battle major technical problems to buy tickets for the group's next tour.

Many fans spent hours trying to access ticket websites and phone lines, which buckled under "unprecedented" demand.

SJM Concerts managing director Simon Moran said a record one million tickets were sold in one day. "We coped with it in the best way possible," he said.

Ticket agency Ticketmaster also said sorry for the "frustrating delays".

Robbie Williams will rejoin his bandmates on the road for the first time in 16 years when they play at least 25 stadium shows in the UK and Ireland next summer.

In a statement, the band said they were "speechless" and "truly and utterly shocked" at the speed of the sales.

"To sell one million tickets in a day is mind blowing and we think we'll be in shock for a few days," they said. "We want to thank everyone who has bought tickets today and look forward to seeing them next year."

More fans will watch the Progress Live tour than any other tour in UK and Irish history - beating the group's previous record set in 2009.

Mr Moran, who is responsible for staging the shows, told BBC News that the technical problems were "unfortunate".

"But it's due to the absolutely unprecedented and never-before- seen demand for these tickets to watch Take That," he said.

"We're over 950,000 tickets sold which is far in excess of anyone's ever done in one day. So it's a case of coping with it as best we're able to."

Although the official ticket agencies regularly updated their ticketing systems, they "didn't work today", he admitted.

"We did our best to ensure we used all of the major ticketing platforms," he said. "They're the market leaders. It's unfortunate but we have sold 950,000 tickets so people have bought them over the course of time."

The website for Ticketmaster, one of the ticket agencies selected, received 20 million page views on Friday.

That was "far in excess" of the number seen when tickets for Michael Jackson's planned comeback concerts at the O2 arena in London went on sale last spring, the company said.

Ticket agents "struggled to cope with the sheer volume of people", Ticketmaster admitted.

"We had planned for the demand for Take That tickets to potentially exceed anything we'd ever experienced before at Ticketmaster, and believed that we would be able to respond," a statement said.

"But we have undoubtedly seen an unparalleled level of demand today and whilst hundreds and thousands of tickets have been sold, we know that many of our consumers have experienced frustrating delays in securing their tickets.

"We apologise for these problems and acknowledge that this is far from the experience we usually deliver."

The band's tour will include seven nights at the City of Manchester Stadium and a further seven at Wembley Stadium. They will also stop in Sunderland, Cardiff, Glasgow, Dublin and Birmingham. Many dates are now sold out.

Thousands of people also queued at venue box offices, while BT said the national phone network received between three and four times the normal number of calls on Friday morning.

Meanwhile, hundreds of tickets appeared on eBay and other secondary websites at inflated prices.

Police have warned fans not to buy from unofficial agencies, which they said may not fulfil orders and may use personal details in identity theft.

Fans wrote to the BBC to express their anger at the difficulties. "Ticket buying is a nightmare!" wrote Louise from Birmingham.

"You would think there would be something in place to prevent the nightmare of crashing sites."

Nik from Ipswich, another fan, said: "It is very frustrating as you don't know if all the tickets have gone or not.

"I don't really understand why the sites can't have more bandwidth or servers at times like this."

Iggy in Barrowford, Lancashire, wrote: "It is madness in this day and age that the ticket companies cannot gear up for days like today.

"As for the tickets already appearing on resale sites, how is this fair to the genuine fans?"