A way to pay for things like a lease car etc by swapping some pay before tax, National Insurance and Pension Scheme contributions are calculated – it reduces your pensionable pay as well as your taxable pay so also reduces your future pension income, especially if in the years used to calculate Final Salary Pensionable Pay (1995 Scheme) or Reckonable Pay (2008 Scheme) future pension income
Lots more information on our Salary Sacrifice page