ITV News has filmed an altercation outside the home of Liberal Democrat MP Mike Hancock, earlier today.
In a statement, a Hampshire police spokesman said: "A reporter received an injury to his nose during the incident.
"Police officers attended and are conducting an investigation into the circumstances surrounding the incident.
"A 37-year-old man has been arrested on suspicion of assault, and is being taken into custody where he will be interviewed by officers today."
Mr Hancock was suspended from the party yesterday following a report on alleged sexual impropriety.
More top news
Men who have been forced by women to have sex against their will are being urged to take part in a new study into the "hidden crime".
Dr Hadiza Bawa-Garba has lost a Court of Appeal challenge against negligence manslaughter conviction over six-year-old Jack Adcock's death.
Brexiteers are crowing "victory at last" over yesterday's overwhelming vote by MPs in favour of triggering Article 50 by the end of March.