NIB operates a Super Saver SSA offering a variable interest rate of 5.75 per cent or 6 per cent for deposits of more than £25,000. NIB says its variable rate for deposit accounts has not fallen for two years.

It also has fixed term special savings accounts. For example, a three-month fixed account will give interest of 5 per cent for deposits between £5,000 and £15,000 or 5.125 per cent for six months, although the same sum deposited for 12months gives a much lower return of 3.25 per cent.