The 63 second clip, posted on video sharing website YouTube, was posted by an unknown user called 'b6alvesisback' and is also thought to be responsible for posting footage of racist chanting at a Wrexham FC game last year.

Local police, who were informed of the footage yesterday, branded the incident 'the worst type of racism' and said they would be doing everything in their power to investigate it.

The clip, filmed by a second person, shows an unknown figure dressed in white wearing a Ku Klux Klan style mask walking down Hill Street in the town, towards Market Street during darkness.

The street is deserted. Towards the end of the clip he reveals writing across his chest which reads 'White Knight', a traditional name for Ku Klux Klan members.

A poster with a remarkably similar name – ben6alves – sparked controversy in August last year after submitting footage of a minority of people at Bradford City apparently making racist chants.

Speaking this morning PC Philip Jones said CCTV footage was unlikely to still remain of the incident, which was posted on Youtube just over a month ago.

He said: "CCTV footage only lasts for a week. But this is the worst type of racism really. We'll be examining the clip closely and if we can gain anything from it we will.

"If anyone has any information we would urge them to come forward and get in touch with us."

The North Wales force has a zero tolerance approach to hate crime.
Figures released earlier this month revealed there were 327 recorded incidents of hate crime across the region in 2007/2008 – 67 less than a year earlier.

However, North Wales's force diversity development manager Greg George said the number was still too high. No one at the North Wales Race Equality Network was able to comment.

Anyone with information regarding the incident should phone North Wales Police on 0845 607 1001 (Welsh) or 0845 607 1002 (English).