Common Assault offences cover both intentional and reckless (sometimes construed as 'accidental') actions. This means that you can be charged with Common Assault both if you meant to hurt someone (or cause them to think they were going to be hurt) and if you didn't mean to.
Oh and before you start whining about fake news and the biased BBC, perhaps you should see this statement from Manchester City.
Manchester City would like to sincerely apologise to Aston Villa goalkeeper Robin Olsen, who was assaulted after the final whistle at today’s match when fans entered the pitch.
Or are the club also part of the anti-City media agenda? I suppose it's only a matter or time.