David Cameron told Nick Robinson why he signed the letter from former PMs; Blair, Brown & Major in writing to the PM…

“None of us, in spite of all the experiences we had had, had ever had to deal with something as difficult as what the current Prime Minister to deal with, so we all felt an enormous sympathy and understanding for the huge task that the government faced. I think all in our separate ways, came to the conclusion that mass testing was a very big part of the answer.”