SURREY, B.C. - Jack Layton brandished British Columbia's HST outrage as a stick to beat the Conservatives in the battleground province, just days after lauding "very progressive" tweaks to the much-maligned tax in Nova Scotia.

It's a stunning contradiction that the NDP leader downplayed Thursday, saying the harmonized sales tax has long been accepted on the East Coast, where it was introduced by Liberal governments in Nova Scotia, Newfoundland and New Brunswick.

"It was in place for 12 years in Nova Scotia," said Layton in a slip of the tongue. The levy -- originally dubbed the blended sales tax until the acronym BST became associated with bovine excrement -- was actually imposed on April 1, 1997.

He insisted there's a difference between the two regions because former B.C. premier Gordon Campbell promised not to bring in the HST, then reversed himself. It ended up costing him his job.

"You don't see that same anti-democratic approach that was adopted here when it comes to Nova Scotia," Layton said.

"What's happened here in British Columbia is that people have risen up and said, that is wrong. You've violated basic democratic principles and we just won't stand for it. That's what we're saying."

In fact, the Liberal government of the day in Nova Scotia made similar promises to people there -- a point the provincial NDP hammered home in at least three elections campaigns, where they promised to abolish the tax.

Robert Chisholm, the candidate running for Layton in Dartmouth-Cole Harbour, was the provincial NDP leader at the time.

Chisholm appeared before a Senate committee pleading for the upper chamber to halt the federal legislation enacting the HST after the provincial Liberals used their majority to "ram through" the tax.

"This tax works like Robin Hood in reverse," he said on March 6, 1997.

"Senators, the Liberals misled and betrayed the people of Nova Scotia. They have no mandate to bring in the BST and there is no support for this tax from ordinary Nova Scotians because, clearly, it is a bad tax."

New Democrats are now the governing party in Nova Scotia and hiked the provincial portion of the tax in their recent budget, bringing the combined levy to 15 per cent.

But Layton prefers to focus on the tweaks NDP Premier Darryl Dexter has made to soften the impact on low-income families.

"We used his proposal for example to take the HST off home heating and suggested that that should happen right across the country. A very good idea," he said Saturday in Dartmouth, N.S.

"You should remove it from family essentials like home heating and other essential items which we think was a very progressive move."

B.C. will hold a referendum in June on whether to scrap the combined 12 per cent tax, which Campbell's government imposed shortly after winning its third straight majority in 2009.

The province received $1.6 billion from Ottawa to grease the harmonization wheels -- a payment Layton has described as a bribe that the Conservatives have threatened to claw back.

The three East Coast provinces received similar compensation payments that totalled $961 million over four years. Ontario received $4.3 billion for harmonizing the GST with its provincial sales tax last July.

Quebec is seeking $2 billion in compensation from Ottawa for agreeing to an HST-style sales tax in the early 1990s. The federal Conservatives promised to a sign a deal with Quebec by September -- if they're re-elected.

Earlier in the day, Layton promised to get tough on crime, particularly gang violence.

The party's strategy would put an additional 2,500 police officers on streets across the country and double funding for programs that try to keep children from joining gangs.

The NDP would invest $100 million a year in a suite of crime-prevention programs, he said. When additional police are factored in, the entire platform plank would total $250 million annually.

An NDP government would also make gang recruitment illegal and make car-jacking and home invasions separate offences under the Criminal Code, Layton said in Surrey, B.C., where violence among young people has skyrocketed.

Law enforcement shouldn't be left alone to tackle violence on the streets and a smart government invests in crime prevention, he said.

"Gang violence is a national problem that requires Canadian leadership," Layton said during a round table with community activists.

"Prevention is the key tool to stamp out street crime at its source."

The Conservatives broke their previous election promise to hire 2,500 more front-line police officers, Layton added.

"Stephen Harper's crime agenda could push prison costs up to $9.5 billion per year by 2015, yet federal spending on crime prevention has barely budged since 2006," he said.