Well yeah they conducted between 15k and 25k tests a day for weeks which was terribly low. I think it was 50k yesterday and 80k today so they made a huge jump. The UK also targets 100k tests a day so if they can reach that they will be one of the top performing countries in that regard. However, it would still take some time to catch up to in total numbers.
To put it in perspective, the UK was at 820k total tests yesterday and with 82k tests a day they can double the totals in only 10 days.
At the start of the crisis the UK was actually testing more than nearly every other country in Europe bar Italy who already had an outbreak in the North. That all stopped when the lockdown started even though we had the capacity to ramp up.
I never understood the reasoning to stop mass testing to track and allocate resources appropriately. We obviously have the capacity. In the small lab I used to work in we could churn out thousands of PCR tests in a single day.