Even using “granted” as a proxy for “eligible”, hard to tell as every source I found contradicts all the others, somewhere between 25 and 75 percent.

However, this isn’t the right question, for two reasons.

First: The number you want to compare against is the people whose minds were changed by the latest policy. Given how few people were seeking asylum in the UK even before this, the maximum is already low.

Second: this policy does not improve the expected accuracy of government judgement regarding the legitimacy of any given claim.