Deputy Labour Leader Harriet Harman called Lord McAlpine's legal action against Twitter users who wrongly linked him to child abuse claims "a wake up call".
The Shadow Culture Secretary told ITV1's The Agenda With Tom Bradby, "It's a reminder that it's [Twitter's] not a no-go zone for the criminal law or the civil law".
"I think Twitter helps with the news. You find out things so much more quickly - that is unless you're the Director General of the BBC," she added.
The Agenda will be broadcast at 10.35pm tonight on ITV1.
More top news
A list of commemorative events as the UK marks a decade to the day 52 were killed and hundreds injured in London terror attacks.
Larger stores could be allowed to open beyond the current six-hour limit on Sundays under a relaxation of rules in Wednesday's Budget.
IS is now attracting women and whole families as well as young men - but will any return to carry out another 7/7?