The breaker that trips will be an earth leakage breaker very probably - taking out both lights and sockets.
The breaker senses a difference between the current in Live and Neutral and the assumption is that the missing current is running away to earth - possibly through a person - which is not good.
It could be anything but there's not much it could be - the plug and cable - possibly but unlikely / The Trigger Switch possible but also unlikely / The motor and its start-run capacitor - much more likely.
Many power tools these days have dynamic breaking to stop the blade quickly - the electronic pack that does that could be defective - also quite likely.
Commercial diagnosis and repair will probably not be cost effective.
B&Q sell an Evolution Mitre Saw for £68
Good Luck..., February 2017
