(edit): eep, some better law people than me posted.. I'll just read over that before I embarrase myself *copied*.
edit: here's the post again. I'm not sure why you lot are talking about trespassing and negligence? The post says he rented out the pitch for £18?
And you can't negligently cause criminal damage. Only intentionally or recklessly. Edit: and I am yet to do property law!
Anyway, the post:
There are two seperate law issues here.. The first is whether you commited criminal damage (Criminal law), the second is whether you will have to pay for damages as a result of the contract (Civil law).
It wont be viewed as criminal damage - the CPS wouldn't bother with the case. I suppose if you refused to pay they could get the police involved, but are more likely to get money back from a civil court by the contract you made to use the pitch. But the law on criminal damage in case your interested (in respect to this) is to whether you were reckless as to the damage being committed. A person acts recklessly (with regard to criminal damage) with respect to:
"i) a circumstance when he is aware of a risk that it exists or will exist,
ii) a result when he is aware of a risk that it will occur; and it is, in the cirumstances known to him, unreasonable to take the risk."
Given that they had designated it a football pitch, it would be quite odd if at all possible to claim you were reckless, though I guess possible under part i. But I wouldn't expect it to reach a criminal court anyway.
So, that that was all hypothetical. I'm really not sure what the law would say here.. On one hand you made a contract which is likely to make you liable for the damage, but on the other hand, if that term is unfair (if the glass was so badly placed it was likely to be smashed when the pitch was used), then you might not be liable. A term is unfair if 'contrary to the requirement of good faith it causes a significant imbalance in the parties' rights and obligations arising under the contract'.
So, *shrug*. I'm sure there's some cases with this sort of thing in them which would set out the law, but I don't know of any. Anyway, I would try and avoid paying for it. Send them a letter saying it was unreasonable make you pay for damage to a pane of glass so close to the pitch, since when the pitch was used for its purpose, the pane was likely to get damaged.