Foghorn toilet sound!

[agarford]

Hi,

When flushing our toilet, it makes a (very!) loud foghorn sound.

Please see the attached video. When I press here, the sounds stops.

Could someone kindly advise what I need to do to fix this?

 

[ShaunCorbs]

Inlet / fill valve needs replacing

 

[Aquarius]

As per Shaun, or at least re-washering.