NEW: No Covid-19 tests at all have been available in much of London all day today, LBC understands. This is the message being given to people with symptoms trying to get tested in the capital. They've been trying throughout the day. More on @lbc at 7.

Government spokesperson: “There is a high demand for tests and to help stop the spread of the virus we are targeting testing capacity at the areas that need it most, including those where there is an outbreak, as well as prioritising at-risk groups."

This is despite there clearly being huge spare capacity. Yesterday there was capacity for 370,000 tests but just 176,000 were processed. That's a fairly typical day - huge excess capacity, despite many people reporting that they cannot get a test.