Now even the Brits admit it: Handing a get-out-of-jail-free card to a terrorist who brought down Pan Am 103 over Lockerbie, Scotland, killing 270, was a mistake. It's about time.

But why stop there? London should now do everything in its power to get Abdel Basset al-Megrahi back from Libya and behind bars, where he belongs.

Washington should hold Britain's feet to the fire on that. And press Libya, too.

"The new British government is clear that Megrahi's release was a mistake," a UK envoy said this week, echoing a statement by a spokesman for Prime Minister David Cameron.

Megrahi was freed from a Scottish jail in August -- ostensibly out of "compassion," after doctors said cancer would likely kill him in three months. (If only.)

But it was painfully obvious even then that Megrahi's release was a sham: At the time, Britain was trying to help close a $900 million offshore gas-and-oil exploration deal between Tripoli and BP.

And though London tried to pretend that Scottish officials independently decided to spring Megrahi, Britain's then-justice minister, Jack Straw, admits that the BP deal was a factor for London.

Straw himself made it clear to his Scottish counterpart that the terrorist's release would boost British interests, writing: "I do not believe it is necessary or sensible to risk damaging our wide ranging and beneficial relationship with Libya" by refusing to let Megrahi go.

BP is set to start drilling off the Libyan coast soon.

On top of all this, one of the doctors who came up with the "three months to live" estimate now says he did so following a suggestion by Libya -- and that it's entirely possible the terrorist, who returned home last year to a hero's welcome, could live another decade.

This whole thing stinks.

And there's just no reason why Washington and London can't try to make things right.

"Both the British and United States have vowed to fight a War on Terror, and if one of the worst terrorists in history . . . can be released for a few coins, or pounds, what does it say to other terrorists?" asked New York Sen. Chuck Schumer.

He and other senators have asked the State Department to probe the deal and want BP to delay its drilling.

That should be just the start, of course.

The families of those 270 victims continue to feel real pain -- not only over their loss, but over this gross miscarriage of justice. Terrorists must be laughing with glee over Megrahi's release -- even as they plan their next attack.

The Obama and Cameron administrations have no right to feel content with mere expressions of remorse.