UK protesters occupied Piccadilly Circus

On 26th of March, a 1 day strike took place against the present government's cost cuts.  Loud music, smashed windows, smoke bombs...I saw some of them just enjoying themselves like at a festival.

Thinking about it, I just wonder what was the real purpose of their strike.  What will these actions bring to us?  Will UK government listen to us and change their decision?  I am a Japanese living in the UK, so I couldn't help thinking about the difference of reactions towards anger between Japanese people and Londoners, although they are living in an isolated island and suffering from different difficult situations at the moment.