Turn on hot tap, boiler ignites, but cold water comes out?

I have Baxi combi 105e boiler, and the hot water has suddenly (worked fine earlier that morning) ceased to work. Never have suffered any kind of flow, temperature problems before.

Now, when i turn the hot tap on:
1) The boiler ignites,
2) The fans starts,
3) Two pronges on the 3-way diverter value push their respective micro switchs ok,
4) Cold water freely flows out of the hot tap.

Central heating continues to work beautifully.