The Government is currently legislating to render the use of exclusivity clauses unenforceable in zero hours contracts. In addition, following a consultation exercise, draft regulations have been drawn up outlining proposals for secondary legislation to prevent employers from sidestepping the ban.
The Government Response to the 'Banning Exclusivity Clauses: Tackling Avoidance' Consultation and a copy of the Draft Zero Hours Workers (Exclusivity Terms) Regulations 2015 can be found here.