No power

by Hans
(West sussex)

Hi there.
I've brought my caravan out of storage to go away next week.
where I store I my caravan I have permanent power. There was power last week everything was working fine battery was a getting a bit flat!
On bringing it home and plugging it into the mains nothing but the polarity light comes on.
Have tried to charge the battery with the caravans charger but the light doesn't even come on.
Has anyone got any ideas?
I would be deeply grateful if someone can help?
Regards
Hans Miles