Tight security means screaming Michael Jackson fans will not catch a glimpse of the reclusive pop superstar when he addresses the Oxford Union next month.

Both the Oxford Union and Thames Valley Police admit they do not know how many Jacko fans to expect when the self-styled 'King of Pop' launches his "Heal the Kids" charity in the city on March 6.

A page on the Oxford Union's website where members can apply for tickets has already received more than 800 hits since it went live at midnight on Sunday.

The union, more often addressed by distinguished politicians than pop stars, has drafted in about 50 security people to surround the star, who will also have his own bodyguards and entourage.

Daniel Johnson, the union's spokesman, said St Michael's Street is to be cordoned off to keep Mr Jackson's fans back.

He warned anyone hoping to see Mr Jackson without tickets, there would be no point turning up.

He said: "We are not entirely sure how many people are going to come.

"We are giving out the message there will be nothing for them to see."

The exclusive tickets will be allocated to 1,000 people. They will be issued on a random basis to those who can prove they are members of the Oxford Union. Friday is the deadline for applications.

The union has about 15,000 members in Oxford.

Jackson is coming to the Oxford Union to launch his new charity called "Heal the Kids" - aimed at bringing parents and children closer together - with US Rabbi Shmuley Boteach and psychic Uri Geller.

Oxford Union president Nick Mason said he thought Jackson chose the Union because of its reputation for oratory.