London 2012: Ticket payments due for withdrawal
The organisers of the London Olympics have started taking money from the accounts of people whose applications for tickets have been successful.
The process will continue until 24 June, when people will be notified of the tickets they have won.
A London 2012 spokesman said people should make sure they have sufficient funds available.
About 1.8 million people made more than 20 million applications for the 6.6 million tickets.
The ticket application process lasted for six weeks, which ended on 26 April.
This will mean that in some cases, money will be taken out of people's accounts before they know which tickets they have been able to buy. The Olympic organisers will be processing the ticket applications up to 10 June.Random allocation
Refunds are not available but London 2012 will launch its official resale platform early next year, through which people can offer their tickets for resale at face value - although there is no guarantee they will be bought.
EBay, the internet auction site, has said it will not allow the resale of Olympic tickets.
Any tickets unsold by organisers are expected to be made available in further ballots, along with the possibility of additional tickets for higher-profile events being released as venues are tested and capacities finalised.
BBC Olympics correspondent Gordon Farquhar said that the remaining tickets would be sold according to a set structure.
He said: "Those who applied and got no tickets will be given first pick in a sale of what's left. Those who got some tickets but not all will get second preference in the remainder sale.
"Those who got them all will get third preference. Only those who applied in the first round of ticketing will get this second chance now, on a first-come first-served basis.
"Later in the year, a general sale of the remainder of the tickets will take place."Card issues
Peter Kelly from Epsom, Surrey, may not have the chance to get Olympic tickets as his credit card company, Barclaycard, for security reasons, has replaced the card that he used to apply for tickets.
He has applied for two tickets for 18 events, totalling nearly £4,000, and described watching the Olympics as "a once-in-a-lifetime opportunity" which he did not want to miss.
He said: "I today received a letter from Barclaycard saying they needed to replace my card. This is the card I used on my Olympic ticket application, so it needs to be working when the London Organising Committee of the Olympic Games processes my application for the tickets, or my application will fail."
A spokeswoman for Visa said that anyone with card issues should contact LOCOG, make them aware of the situation, and provide details of their new Visa card.
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Stephen Hunt, an insolvency practitioner from London, has bid for £36,000 worth of tickets.
"I paused when I saw how much I was applying for, how much it would actually come to but if you think about it, it's like rolling or getting heads twenty times in a row," he said.
"The chances of me getting all my allocation are almost nil, in fact the chances of getting one ticket out of that lot is quite small.
"I sort of took a range of things I wanted so the 100 metres, the opening and closing ceremonies, then it's my daughter's birthday in the middle so something for her in the gymnastics.
"If I can get two or three, hopefully one for my daughter's birthday, I'd be happy."Completely random
The opening and closing ceremonies were expected to be massively over-subscribed, as well as big athletics events, swimming nights, track cycling and some of the cheaper tickets.
Many people applied for several events, hoping to boost their chances of getting tickets.
Standard prices range from £20 to £2,012 - the top ticket for the opening ceremony - and oversubscribed events will be decided by a ballot.
Ticket allocation is completely random, so some unlucky applicants might end up without any, while others may be allocated all the tickets they applied for.
A further two million tickets for the Paralympic Games go on sale on 9 September.