The UK now has a lower 14 day new case incidence per 100k population than many of the countries on the Cat A list.
There are hardly any private medical facilities in the UK that will guarantee to turn around the PCR test within 72 hours (actually more like 65 hours, as travellers will need the certificate before heading to the airport). And that’s not to mention the cost for a family.
NHS tests are easily available but are not for travel purposes, they are only for people who feel they may genuinely have symptoms. And in any case the results are just by text/email not a signed certificate.
If the 100,000 visitors for August target is based on a significant % of UK residents then the Minister will be disappointed.