The producer of Madonna's first live webcast estimates that 9 million fans watched the pop icon's concert over the Internet on Tuesday night, shattering Paul McCartney's world record for most-viewed webcast. But perhaps more importantly, the performance might foreshadow a summer tour.

The show, at London's Brixton Academy, was Madonna's first concert in England in seven years. Some 3,500 attendees — radio contest winners, various invitees and a smattering of celebrities — saw Madonna perform in person, but 9 million watched via the Internet, according to Nicky Price, a representative for Microsoft's MSN, the webcast's producer.

Madonna's publicist, Liz Rosenberg, said Madonna is "thrilled to pieces" about the webcast's success.

But the most joyous thing is that she was reminded how much she loves to perform," Rosenberg said, adding that a summer tour is a distinct possibility.

Madonna treated London fans and millions worldwide to

the same kind of blink-and-you-missed-it half-hour performance that New York fans got at Roseland earlier this month. According to Rosenberg, Madonna whizzed through "Holiday" and a quartet of songs from her new album, Music, including "Runaway Lover," "Impressive Instant," "Don't Tell Me" and the title track.

Until Madonna's webcast, McCartney held the record for most-viewed webcast, according to Reuters — his performance of '50s rock and roll classics at Liverpool's Cavern Club last December was viewed by an audience of about 3 million over the Web.