As Murray trains, fans join the line for tickets

Tickets for today's Wimbledon quarter-finals were changing hands on the internet for as much as £1,750 last night as expectations for Andy Murray's assault on the Championships grew to feverish levels.

At the All England Club last night, thousands of people unable to afford the inflated prices had formed an immense queue in the hope of securing tickets. Some had been there since 5.30am on Monday, before Murray's place in the quarter-finals had even been confirmed, queuing in temperatures of up to 31C. St John Ambulance treated 132 people yesterday, mostly with heat-related problems. One was taken to hospital.

This year's tournament has captured the imagination of the British public more than any other in recent memory. By the end of the first week, 266,264 people had attended the tournament, an increase of more than 24,000 on the same week last year. Almost 100,000 people queued for tickets in the first week alone, an increase of about 13,500.

Monday night's thrilling match, in which the Scot defeated Stanislas Wawrinka over five sets, attracted an average of 8.6 million viewers – beating even the Champions League final in May which was watched by an average of 8.3 million people. Last year's epic men's singles final between Rafael Nadal and Roger Federer averaged only 7.4 million viewers.

The Murray v Wawrinka match ended at 10.39pm, the latest finish in history. It was played under floodlights and the new Centre Court roof. The moment Murray hit the winning forehand, 12.6 million people were watching on the BBC.

Ticket exchange websites reported high levels of interest as more people considered buying seats for the tournament's few remaining matches, hoping to see a Brit win Wimbledon for the first time since Fred Perry in 1936.

The face value of a ticket for Murray's quarter-final match against the former world No 1 Juan Carlos Ferrero is £70. Last night, seats were listed for up to £1,750. If he gets through to the semi-finals, Murray will play again on Friday. A seat for this day already costs up to £3,729. Tickets for Sunday, when the men's singles final will be played, were on sale for up to £4,814.

Eric Baker, from the ticket exchange website Viagogo, said: "Tickets to Wimbledon are attracting a huge amount of interest... the number of people searching for them on Viagogo is up 300 per cent on last year. Tickets to see Andy Murray are really driving sales – every time he wins, ticket prices for the final jump higher. They are currently trading for about £5,000, but if he keeps winning, I expect some of the best seats will go for twice this."

Seatwave, another ticket exchange website, said it had sold four times as many tickets for this year's tournament as it did last year. A spokeswoman said that since Murray's first win, the average ticket price had increased by almost a third for every day he remained in the tournament.

Vasilisa Alexender, 19, from Moscow, was first to join the queue for tickets for today's quarter-finals, lining up at 5.30am on Monday. She said: "I was amazed that I was first, but now there are several hundred behind me.

"I love the Russian players and Roger Federer, but Andy is such an exciting player to watch. His match against Wawrinka was fantastic. Andy really fought to win. I watched it on TV at somebody's house in Wimbledon village after they invited me in. All you could see was the flickering of TV screens from people's houses."

Also queuing was Louise Payne, 18, a student from Fareham. She said: "Andy is so cool that I would queue for a month to see him play. We just have to have a British winner." Her friend, Anna Pastellas, also 18, said: "The fact that so many people are queuing for Andy just shows how desperate we all are for him to win Wimbledon."