Claim: The Treasury forecast that dropping out of the European single market will cost the economy £66 billion and reduce GDP by 7.5%.
Fact-check: Leaving the single market - Full Fact
Verdict: this is confusing estimates for gdp with estimates for tax revenue. the treasury does expect gdp to be 7.5% lower than it otherwise would have been after 15 years, if the uk relies on world trade organisation rules outside of the single market. but the £66 billion figure is for the resulting loss to public finances, not the economy, and it's the upper limit - £52 billion is the treasury's best estimate.
Organisation: Full Fact
Author: Richard Braham
Date published: 2016-10-12T00:00:00