Liffe, the London-based futures and options exchange owned by NYSE Euronext, is planning a model similar to its main rivals by offering clearing services to customers, according to sources close to the exchange, a controversial move that could slow the launch of Project Rainbow, the putative trading system backed by investment banks and brokers.

The plans, which were first reported in Financial News last week, also throw into doubt Liffe’s relationship with its current clearer LCH.Clearnet.