Chief secretary to the Treasury Paul Boateng has admitted the rules over stamp duty on commercial properties will have to change.

In a letter to shadow chancellor Michael Howard he says the rules will have to be amended "over the next couple of years".

Forum Response: Royal Institute of Chartered Surveyors

David Melhuish, senior policy officer at RICS, said: "There are a lot of complex issues that remain unclear or still out for consultation and inclusion in further legislation in due course. There's lots to do with more complicated transactions they have barely scratched the surface of."

Forum Response: British Property Federation

A spokesman for the BPF told ePolitix.com: "The BPF supports the call for a delay in implementing the reform of lease duty and agrees that insufficient time has been allowed to consider alternatives to the proposals.

"If more time is not provided for proper consultation we will be left with an imperfect regime and it is inevitable that changes to the legislation will be needed in the years ahead. This will create more uncertainty.

"All indications are that leases are not used for avoidance - so we find it difficult to understand the need for such speed.

"We do not believe the Inland Revenue's view that 60 per cent of commercial leases will be exempt from the new lease duty and will be lobbying for mitigating measures, for example raising the threshold and a reduced rate of tax at least at the lower end of the market to help to ensure that businesses can move when they need to.

"We are also concerned about the effect on the property investment industry and are looking for an increase in the discount rate so that crucial development projects do not fail to go ahead because of the new tax."