The Tessa only ISA, tongue twistingly known as a Toisa, was another special tax-free product. Old style TESSAs, the forerunner of the cash ISA, lasted for five years and then matured. If this occured any time between 1999 and 2004, the TESSA automatically turned into a Toisa.

Since April 2008, all Toisas have become simple Cash ISAs, meaning all normal ISA rules apply . You can no longer add any more funds to an old Toisa, but if you have any money left in one, you can transfer it and up the rate.