Standard Life has surprised rivals in the fund industry by promising to pay an income tax liability due from investors directly to HM Revenue & Customs on their behalf.

The regulator is clamping down on the "cashbacks" investors receive from online investment platforms by way of a discount, to ensure transparency of charging. Ahead of a ban on such rebates from 2014, HMRC last month unexpectedly made the cashbacks subject to income tax.

Standard Life said earlier this week it had "agreed with HMRC to pay the fund rebate income tax liability until the end of December 2013 direct to the Revenue on behalf of all Standard Life Wrap and FundZone customers". They would now have no liability to declare on their tax return.

Some platforms such as Alliance Trust Savings already offer entirely rebate-free funds and Standard said it was "working to remove the rebate mechanism from its pricing structure by the end of 2013".

David Tiller, head of platforms, said the group felt "a responsibility to do what we could to give advisers and their clients the time to plan for this liability in the future".

But according to other leading providers questioned by Money Marketing magazine, Standard's initiative will not be copied by rivals.

Edinburgh-based Nucleus along with Skandia, Ascentric, Cofunds, Aviva, Transact, and Novia all have no plans to intervene in customers' tax.