Robbers held up a security van at Heathrow Airport yesterday and escaped with $6.5 million in American currency that had just arrived from Bahrain, police said.

Police said the driver of the van was attacked by at least two men at the airport's Terminal 4 at about 6:30 a.m. The robbers forced him to the ground and bound his wrists before transferring the cash into another van.

The money had just arrived on British Airways Flight 124. The theft of the eight red cargo boxes of cash occurred as the 187 passengers left the plane and it was being refueled. Within five minutes, all airport security gates were closed, but the robbers were already gone, police said.

The attack raised questions about the effectiveness of efforts to strengthen security at Heathrow after Sept. 11. It was unclear how the robbers got into an area reserved for airport personnel and how they knew their way around.

The second van was later found abandoned and burned nearby, with no trace of the cash or the suspects. Police said they were seeking two males in connection with the robbery.

The guard suffered shock and wrist injuries. Police said the man did not report seeing firearms during the robbery.

In 1983, robbers posing as security guards stole 26 million pounds ($37 million at today's rates) worth of gold bullion from a warehouse at Heathrow. The men were later arrested, but most of the gold was never recovered.

A British company claimed in federal court yesterday that it owns the patent on hyperlinks - the single-click conveniences that take a Web surfer from one Internet page to another - and should get paid for their daily use by millions of people.

But a federal judge with a laptop on her desk warned that it may be difficult to prove that a patent filed in 1976, more than a decade before the World Wide Web was created, somehow applies to modern computers.

"The language is archaic," said U.S. District Judge Colleen McMahon. "It's like reading Old English."

She said comparing a 1976 computer with a 2002 computer is like comparing a mastodon and a jet. And she suggested that the invention at issue "was already outmoded by the time it was patented" in 1989.

But Albert Breneisen, an attorney for British Telecommunications PLC, insisted, "The basic structure of linking is covered by the patent." Before BT's technology, he said, a computer user had to know and enter the complete address of another page.

At a preliminary hearing in White Plains, lawyers for BT and for Prodigy Communications Corp. - the Internet service provider that is the first target of the lawsuit - argued over the meanings of words as simple as "central," as in "central computer," and phrases as complex as "means coupled to said further memory means."

"'Central' is a simple English word," the judge said, to little avail, as the lawyers used slide shows, animations and charts.

BT tried to persuade the judge to interpret the language broadly for the jury - to include a computer mouse, for example, as the "keypad" mentioned in the patent.

"It has keys," BT lawyer Robert Perry said hopefully.

When they argued over the word "terminal," Prodigy lawyer Willem Schuuman tried to show that the "dumb" terminals of old cannot be equated to modern desktops that do their own computing.

The judge said she feared that jurors, who may have a hard enough time understanding their own computers, will not be able to grasp what computer technology was like in the 1970s, when mainframes the size of a Buick had less power than some handheld devices today.

"I'm thinking of the six, eight, 10 people who will not have a clue and will be terrified going into this," she said of the still-to-be-selected jurors.

But BT's Breneisen said outside court, "I think a jury that uses clicks on their computers every day will be able to see how that relates to this patent. It's an old patent but it's got an awful lot of similarities to certain things that are being used on the Internet."

If it is successful against Prodigy, which is now based in Texas but formerly was in White Plains, BT could challenge other Internet service providers and demand licensing fees that might add to members' costs.

At one point in the hearing, Prodigy referred to a German article about technology that existed before the BT invention, and the judge asked unsuccessfully for Schuuman to tell her what the article said.

"I only read German when I'm singing Bach," the judge said.

Two federal police agents face charges that they not only cooperated with drug traffickers, but helped one escape by switching him in custody for another man, the Justice Department said yesterday.

Sixteen police agents were hauled into custody by army troops several weeks ago after the escape was detected, Justice Department internal auditor Angel Buendia said at a news conference.

The scheme began when the Navy arrested a man described as a mid-level operative in the Gulf cocaine cartel in September near the U.S. border. Suspect Rogelio Gonzalez was carrying a small amount of cocaine and about $50,000 in cash.

The Navy turned Gonzalez over to federal police; but instead of booking him, the two agents apparently paid another detainee to take his place at his arraignment, and let Gonzalez go.

Those agents face escape and drug charges. Four other federal officers and three state police from the northern state of Tamaulipas face drug charges. Seven other agents detained in the case were freed with no charges.

Gonzalez, who flashed a false police identification card at the time of his arrest, remains at large.

Buendia said more than 600 federal policemen have been placed under investigation or charged for corruption or administrative violations, and at least as many have been fired for similar reasons since President Vicente Fox took office 14 months ago.