No water coming out of any hot taps!

I was in the middle of my shower this morning after my wife had had hers and the water just started trickling and went cold. There is no water at all coming out of other hot taps in the house with seperate taps.
Heating is working fine.
The boiler heats the water and stores it in a storage cylinder in the cupboard.
Any ideas?

check storage tank hasnt frozen or ball tap stuck shut other than that can only be airlock

get hose on cold tap, connect to hot tap and force air out with mains pressure

Thanks Argent, by storage tank do you mean the cold water one in the loft?

Check all the pipework and tanks in the loft, quite likely something has frozen. If the cold storage tank is empty then it'll be the mains feed to it, carefully inspect to make sure the pipes havent split anywhere before attempting to defrost otherwise you'll get wet.....

I posted the original question while I was at work. When I came home there was some hot water coming out of the hot taps, but then it seemed to run out again. I went up to the loft and checked all the pipes and tanks and everything seemed to be fine and in good working order. All the pipes are well lagged so it should be okay.
I was then going to use the hose to try and clear an air lock, but trying it again the hot water seems fine. Although strangely the bath water won't drain away. Could it have been an airlock that stopped all the hot water that has cleared itself? And is the blocked bath drain related or just coincidence?
Thanks for your help.

I reckon you have had a freeze....with these temperatures, even pipe lagging has its work cut out.
Take the larger tank lid off, see that its full and the ball valve is working.
if thats ok, the copper cylinder is fed by a 22mm pipe from the bottom of the loft tank and the obstruction could have been anywhere along its length.
The bath drain problem is a coincidence and if you have a dripping tap this makes the likelihood of freezing much greater. Pour some salt into the bath plug hole to prevent this happening.
John