The Britain in Europe campaign has published a very good list of 25 reasons not to vote UKIP, here. Some of it is stuff previously covered here, but this was news to me:
“John Brayshaw was exposed on 5 February 2004 as being simultaneously Chairman
of UKIP’s Vale of York branch (since October 2003) and BNP National Treasurer
(since 2000). According to Andrew Edwards, he was also UKIP -BNP “pact liaison
officer for the north”. UKIP denied that they knew of his BNP links despite the fact
that he stood as a BNP parliamentary candidate in Bradford North at the 2001
general election. Brayshaw was eventually expelled from UKIP in 2004 when his
BNP membership became public knowledge.”