The top civil servant in charge of tax at HM Revenue & Customs (HMRC) gives an exclusive interview to Money Box following the news that mistakes have been made with 6 million people's tax contributions.
It is thought that millions of people have overpaid or underpaid tax over the course of the last two years due to mistakes in their tax codes.
Permanent Secretary for Tax, Dave Hartnett is the senior tax professional at HMRC.
He talks about the letters which are being sent out, informing people of the errors made with contributions made through the PAYE system.
Also, Money Box talks to benefits expert Rachel Hadwen, who explains how under or overpaying tax could have an effect on some benefits.
Prison current accounts
Prison accounts were launched 5 years ago
Can offering bank accounts to prisoners help to cut crime?
Paul Lewis asks inmates at HMP Ranby in Nottinghamshire, why they think opening a bank account will stop them from reoffending.
Research suggests that 39% of prisoners who open a bank account reoffend when they are released, compared to the national average of almost 60%.
Yet less than half the prisoners in England and Wales can access accounts, which are offered by The Co-operative Bank, Halifax and Barclays.
HM Prison Ranby is a Category C men's prison
We speak to Tim Franklin, chief operating officer of The Co-operative Financial Services and Chris Bath from UNLOCK, the National Association of Reformed Offenders.
How should we measure inflation?
The Office for National Statistics puts too much emphasis on the Consumer Prices Index (CPI) as a way to measure inflation according to the Royal Statistical Society.
In a letter to the UK Statistics Authority, which oversees the Office for National Statistics, the president of the society, David Hand, has set out his concerns over the use of CPI and other measures of inflation.
These include the way data is handled to come up with the inflation figures that are published.
To explain these concerns, we speak to Jill Jeyland, Vice-President of the Royal Statistical Society.
BBC Radio 4's Money Box: Saturday 11 September at 1204 BST and Sunday 12 September at 2102 BST.