The IR35 battle between contractors and the taxman is thawing, according to one expert.

Dave Chaplin, chief executive officer of Contractor Calculator, said that although the coalition has asked for a negotiation over a successor to IR35, contractors should still be wary.

Neither contractors nor HM Revenue and Customs (HMRC) should assume the new law is going to land in their favour, he says, calling for a simple, objective and unambiguous treaty that is easy to understand.

"It should no longer be necessary for judges and employment law 'experts' to intervene with decisions and opinions over what ought to be a straightforward, day-to-day process," he wrote.

Mr Chaplin added that it is essential for the new rules to ensure that there can be no return to the "arms race" whereby HMRC would develop a new tactic to catch more contractors inside IR35, the freelancers would find a way round it and the tax office would once again tighten the rules.