All hot water taps have suddenly stopped running. Central heating radiators are still OK, and the pipes leading from the hot water tank are all hot to the touch. After a short period there is enough water in the pipe to fill a bowl (1-2 litre), but then it runs dry again. Can anyone help!

What's your location? Are the hot water pipes on a outside wall? Can you track along the hot water supply and see exactly where you have the heat loss? Let me know. Tom