noisey toilet when flushed

[natalia407]

Dear All
I wonder if you are able to help me. I have 2 toilets in my house, 1 upstairs and 1 downstairs. the problem only occurs with the upstairs toilet in that when I flush it about 10 seconds later it makes a horrendous noise - it gradually goes off, but the noise is very loud and means that during the night we can't flush the chain as it will wake the kids.
Can anyone tell me what the problem is and what I should do to get it sorted. many many thanks
Nicky (UK)