Britain’s government on Wednesday abandoned any pretense that leaving the European Union would lift the economy, instead presenting its own plan to leave as the least destructive option.

The government’s switch in its argument followed publication of a bleak official economic analysis of life outside the European Union, which showed that under terms similar to those in Prime Minister Theresa May’s plan for the withdrawal, known as Brexit, Britain’s economy would be 3.9 percent smaller than it would have been if the country had stayed in.

In the government’s worst-case scenario of leaving the bloc with no deal, Britain’s economy would lose 9.3 percent of the gross domestic product it could otherwise have expected.

And that seemed relatively tame compared with a report from the Bank of England also released on Wednesday. In the event of Britain crashing out of the European Union without a deal, the bank’s analysts said, the economy would shrink by 8 percent in a year, house prices would sink 30 percent and the pound would drop to $1.10 from the current $1.27.