Red glow in the sky

Went out for a walk in the lanes this morning and just had to take a shot of this strangely coloured sky. This was not at sunrise but in the middle of the day (nearly noon), the sky was full of grey clouds but in the distance, behind the trees, there was a red glow, like you would see at sunrise.
It was very cloudy, dull and cold when we went out but by the time we got back the clouds had all cleared and the sun shone in a beautiful blue sky - got my timing wrong again ;-))