STSM141030 - Stamp Duty and SDRT Administration: Stamp Duty Administration: section 14 SA1891 - duly stamped
Due to section 14(4) Stamp Act 1891 an instrument that is not duly stamped cannot be used for legal purposes (except as evidence in a criminal action) if it is executed in the United Kingdom (UK) or if it relates to property in the UK or anything done or to be done in the UK such as registration of a transfer of ownership by a Company Registrar.
Under section 14(4) SA1891 an instrument is not “duly stamped” unless it has been stamped with the proper Stamp Duty, penalty and interest with which it is chargeable - see STSM141020 for details of how this is done by HMRC.
In addition, under section 17 SA1891 a penalty of up to £300 may be incurred by anyone who registers or records an instrument which is not “duly stamped”.