CALGARY — According to Premier Danielle Smith, the costs of Alberta leaving Canada have been significantly underestimated by leaders of the independence movement.On Tuesday, the premier told reporters her government’s preliminary analysis of Alberta becoming a sovereign nation paints a very different picture than the one put forward by groups such as Stay Free Alberta, which says Alberta would enjoy lower taxes, stronger economic growth and an easier time approving projects such as pipelines. "I think I came up with almost $400 billion worth of transitional costs that we'd have to assume, in addition to somewhere between $25 billion to $50 billion worth of annual costs," Smith told the media in Calgary on Monday.Smith pointed to the United Kingdom’s Brexit vote in 2016, which saw voters choose to leave the European Union by a small margin, after which many of the anticipated benefits failed to materialize..Finance minister questions claims Alberta would be richer outside Canada.“It didn't actually work out the way they anticipated,” Smith said of the UK.“All of our trade agreements would have to be renegotiated. That includes CUSMA, the [Comprehensive Economic and Trade Agreement] and every other trade agreement that has been negotiated. You don't get grandfathered in on those. So that would cause a disruption in the economy.”She also brought up a point that was made by former Premier Jason Kenney during his debate last month against pro-independence lawyer Keith Wilson about Albertans being able to maintain their Canadian passports after becoming a new nation.“UK residents had to use the long line when they went to various European countries because they had to travel under a different passport,” Smith said, again citing the post-Brexit experience of British citizens..“These are the kind of things we have to be realistic about, and we have some indication based on the UK's ten-year experience that it certainly didn't pan out the way they expected... I think people need to be realistic about what kind of costs and inconveniences they would have in their life if they decided to vote to [leave]," she said.Smith said that if Albertans want to send a message to Ottawa, they should vote to give her government the “authority to change our immigration system, to tackle issues around the Senate and appointing judges and getting the federal government out of our provincial jurisdiction.”“That's the way to send a message.”The premier added the government will be continuing its review of the implications of Alberta independence and plans to release more information before the referendum vote on October 19.