Problem with leaky toilet

[markthedoc]

I've just moved into a new house & have noticed the toilet has a bit of a leak (fills about a mug a day!). The leak comes from the connection on the bottom right of the toilet, its a plastic pipe with a thread on it from the toilet to a metal/copper pipe with a nut on (looks quite old). Is it likely just to be a knackered seal? Is water likely to start guishing out if I undo the nut? As u can probably gather I dont know a great deal about plumbing but fancy having a stab at sorting the problem out myself. Any help gratefully received

 

[MANDATE]

IT's not clear just what or where the leak is.
It sounds as if the leak is from the cistern(tank) that holds about 2gall of water.
Some of these have water feed pipes and over flow pipes that are side entry and some have them bottom entry
overflow pipe is plastic so I assume your problem is associated with a bottom entry water feed inlet pipe
Before dismantling you need to turn off the water supply then flush to get rid of most of the water and scoop the rest
Be prepared before you start by obtaining rubber washers and sealing compound
Also give yourself enough time to obtain replacement parts if things go pear shaped B&Q arn't open Sunday evening

 

[markthedoc]

Jobs all done, cheers for the help Mandate