A message from UKIP Leader Nigel Farage:
"We have an important set of elections on May 5th in which UKIP can make some significant breakthroughs. But at the same time we have to fight a referendum campaign and our frontline spokesmen need to be free to comment and campaign on the main issues.
"Accordingly I have made some changes to our structure today.
"Both of our Deputy Chairs are candidates in the upcoming elections and this will limit any role they can play in the national referendum campaign.
"So I thank Suzanne Evans and Neil Hamilton for their time as Deputy Chairs and announce they will be replaced by Diane James and William Dartmouth.
"Diane will have responsibility for speaking on the issue of security in the campaign and William on trade and jobs. I know that both are free to campaign on a full time basis."