TAX officials are “bullying” in-debt callers into paying more upfront than they need.

Customers including the self-employed are often bamboozled by the complicated tax system and fall behind.

Under a deliberately misleading policy, officials refuse to mention the minimum amount they would accept to set up instalment plans for outstanding tax bills.

Instead they suggest sums that might be more than the hard-up caller can afford.

Patrick Sullivan, of the Parliament Street think tank, said: “Once again bullying tax chiefs are raking in cash from those who are struggling the most.

“All staff should be instructed to give honest advice in the best interests of the taxpayer.”

John O’Connell, of the TaxPayers’ Alliance, said: “A twisted and complicated tax system means people sometimes fail to make payments, especially the self-employed. Staff must not force people into doing something they don’t need to.”

The tactics, understood to have been introduced last month, are displayed on call centre screens.

The “hints and tips” on “maximising” payments include challenging “the customer’s offer, even if the initial offer meets our expectations”.

A report in December rapped tax bosses for failing to consider if taxpayers were treated fairly.

HMRC said: “We are supportive to taxpayers with debts, especially vulnerable customers, and continuously review guidance.