Glyn H is correct.
But to be safe you must always check with local bye-laws, H&S, and IE regulations, these regulations are constantly up-dated and I'll give you and example.
If I was to ask you if you were allowed to install a socket out-let into a bathroom, you would all come on here shouting NO, you can't do that its illegal, well guess what?
You would all be wrong?, I just bought my new updated copy, know as IEE Regulations 17th edition at a cost of £65 and it clearly states the new changes from the 16th edition and installing a socket into a bathroom is now legal BUT you must follow the guidelines set out in the 17th edition.
Using 240v outside is not illegal on building sites it is also NOT illegal but building sites took the lead in following H&S guide lines regarding the use of 240v against 110v, more people were killed on building sites through the use of 240v, there have been no reported deaths since the introduction of 110v on building sites.
If you are going to use 240v outside then use the proper equipment and not bodged up diy electrics or make do's, you can't smell electric, you can't see it, but IT BITES hard and if your wet the resistance in your body is lowered to an extent that if there is a fault in your leads and improper gear, then the chance's are your DEAD.