A FIRST Great Western train out of Swindon had to reduce speed after stone-throwing vandals broke a window.

The 4.15pm from Bristol Temple Meads to London Paddington was attacked as it left Swindon station yesterday.

A stone broke the outer layer of glass of one of the passenger windows.

First Great Western spokeswoman Elaine Wilde said: "It could have the potential for a serious accident, these sort of incidents always increase in the summer holidays."