Who ya gonna believe about tax-free shopping: All those signs at the Delaware state line, or a giant pink bear carrying pastel shopping bags in the London subway?

The Pennsylvania Tourism Office is telling Britain to trust the critter.

In a cutesy overseas ad campaign, the Keystone State proclaims itself to London tube riders as the "Home of tax-free shopping. And bears."

But Delaware, which has proudly bragged for a decade on the Internet and the roadside about being the home of tax-free shopping, has taken some umbrage.

The First State was first to claim the slogan - and, arguably, the more accurate, as it has no sales tax at all, while Pennsylvania has a sales tax on most things besides clothing and shoes.

U.S. Sen. Thomas Carper (D., Del.), who as governor ordered Delaware to post "Home of Tax-Free Shopping" signs at highway entry points, dryly noted Friday that before 1776, Pennsylvania was part of his state.

"Obviously, there are some Pennsylvanians who never got the word about us giving the commonwealth its independence," Carper said.

The Pennsylvania Tourism Office spent $23,000 in the spring to put up dozens of the posters featuring the brightly tinted black bear, and they have been a hit across the Atlantic.

Britons have e-mailed state officials to ask for copies of the signs. A handful of bemused observers have posted pictures of the ads on photo-sharing sites, usually remarking on the goofy, surreal shopping beast that apparently roams Pennsylvania.

The poster surprised Mallory Mershon, 21, a Stevenson University student from Seven Valleys in York County, who discovered it in a tube station during her two-month internship at a London design agency this summer.

"I chuckled," she wrote on her blog. "Besides the absurdity of a shopping bear, who wants to travel across the Atlantic Ocean to visit Pennsylvania?"

In an e-mail, Mershon added that although she likes living in Pennsylvania, she thinks the "home of tax-free shopping" claim is misleading at best.

"It's also probably not the best idea for Pennsylvania to be ripping off Delaware's slogan," she wrote, "even if it is an ocean away."

Delaware's Tourism Office does not have the budget for much overseas advertising. Thus, Pennsylvania's campaign is going unchallenged, even if it might result in Britons' being dismayed by certain receipts at the King of Prussia mall.

"I'm just not going to get into a dispute over who's got tax-free shopping and doesn't have tax-free shopping," said Linda Parkowski, Delaware's director of tourism. "Delaware is the home of tax-free shopping and has been for a very long time."

The ad was assembled by Philadelphia's Red Tettemer agency, where the shopping bear was the latest in a series of tourism-touting posters featuring odd juxtapositions of Pennsylvania assets.

Previous entries included a statue riding a bike (history and biking) and a car driving through an amusement park (roller coasters and road trips). Then came the shopping bear, a nod to the state's large black-bear population. It was presented last year as a massive outdoor banner in Toronto.

"People thought it was a funny-looking image," said Greg O'Loughlin, account director at Red Tettemer.

The Toronto sign bore the slogan "Wildlife and shopping," which the agency decided to retool when state officials wanted to advertise in London.

Places looking to attract European travelers often promote tax-free shopping, O'Loughlin said. So Pennsylvania put its signs in London tube stations at Leicester Square, Piccadilly Circus, and about 30 other stops.

"We're not saying that other places don't have it," Richard Bonds, Pennsylvania executive director of tourism, said of tax-free shopping. "And, well, ours is on clothing and shoes."

He said the tourism office had not received complaints about the accuracy or originality of the ad campaign but had been mailing PDFs of the large posters upon request to the shopping bear's fans.

"This is a different kind of thing," Bonds said. "I think people chuckle when they see it."

Except in Delaware. And when Chicago hears about this, a call could well come in to assert which place is properly called home of the Bears.