Like many people, I had always thought the answer to the question in the title was `never´. How can it be acceptable to treat someone badly because of their race, background, or the colour of their skin?
But over recent weeks I've been sickened to discover that in the minds of some people there is, apparently, an exception. In the event that racism is directed at a Ukip member, it seems to be open season for such comments.
Last week, we had the Labour North London Twitter account which described Ukip as being full of "evil money grabbing Jews". The Labour Party eventually managed a lukewarm denial that the account (which bore the Labour Party logo and was followed by various Labour MPs and MEPs including one of my own North East Labour MEP colleagues) was official.
Part of my North East England constituency is Stockton. Our prospective candidate for Stockton North, Mandy Boylett, is Jewish. She received a letter from her local Labour MP which essentially accused her of being anti-Semitic. When she complained of this treatment, a second letter was published on the MP's website - circulating her personal details online for all to see. Mandy wrote to Ed Miliband, suggesting that the Labour leader might care to intervene. The Labour leader's office didn't even respond.
At a recent by-election in Thurrock, the Conservative Party literature referred to Tim Aker MEP as Timür, taking a side-swipe at Tim Aker's Turkish heritage. Can you imagine what an outcry there would be if Ukip were to resort to such tactics? Yet the Conservatives' MP for the area suggested that it probably 'helped' Mr. Aker. Yes, she actually expressed the view that Tim Aker should be grateful for being a victim of racism. A Labour Party activist followed up by tweeting a picture of Tim Aker next to a Turkish delight wrapper - before continuing his rants by describing him as 'the village's idiot'.
Not so long ago, Ukip ethnic minority members were subjected to sickening chants of 'Oreo' and 'coconut' for attending a Ukip event.
These are not isolated incidents, and this is hardly an exclusive list. Where is the media outrage to accompany these events? Where are the suspensions from the
But it seems that such things are shrugged off, considered acceptable when the victim is from Ukip.
I shouldn't have to point this out - it should be obvious to every right-thinking person that racism against anyone is unacceptable - but racism is racism, whether the victim is Ukip or Liberal Democrat, Conservative or Labour.
Who is to blame when society looks the other way and ignores such racist outbursts? Should the media publicise such incidents even when they're committed against Ukip? Should the Labour and Conservative parties take disciplinary action against racists within their parties just like Ukip do?
Or will bigotry continue to win out - leaving those who wish to spew their vile hatred free to consider racism a fair weapon in their quest to smear the name of Ukip?