The Financial Conduct Authority will ditch "non-critical" work to find £14m, while the rest will come from reserves and fees from the financial industry.

Last year, the FCA had to find an extra £2.5m for Brexit work.

The costs were revealed for the first time in its business plan for the coming year.

The Brexit bill is the dominant issue in the 60-page document, which also outlines FCA priorities including tackling poor pension advice and investigating treatment of longstanding insurance customers.

Andrew Bailey, FCA chief executive, said: "Uncertainty around Brexit is a challenge. We must be prepared to adjust [our plan]."

He said that preparing for Brexit could not just be added on to everything else the regulator would otherwise do.

"It's not feasible for us. It is not feasible for industry," he said.

Switching priorities

The FCA's sums assume a deal is done between the UK and the EU, and he said a transitional deal would be welcomed.

Last year, the regulator hired 15 lawyers specifically to oversee its Brexit preparations.

The FCA is required to give technical support to the government, and help prepare the regulatory regime in the UK for life outside the EU.

It said it would "reprioritise", as well as "delay and reduce non-critical activity" to save money from its existing budget to cover £14m of the Brexit bill.

Projects such as creating a digital archive of company filings will be postponed to free up funds.

Another £5m will come from FCA reserves, and the same amount will be raised from fees levied on large firms that are most likely to be affected by EU withdrawal.

The final £6m will come from specific fees from the FCA's extra work. For example, credit rating agencies will come under the FCA's regulatory umbrella this year, and be charged a fee as a result.

Sarah Isted, financial services partner at accountancy firm PwC, said: "This year, despite politically agreed transitional provisions, the FCA has formally called out EU withdrawal as a key risk and challenge - both for firms and importantly for itself.

"The regulator is illustrating the amount of work still to be done, and shows why firms need to keep their foot on the gas of Brexit planning."

Stephen Jones, chief executive of UK Finance, which represents the UK's major banks, said: "The FCA has rightly prioritised its EU withdrawal work given its impact on markets, customers and member firms."

Why does home insurance always get more expensive?

The FCA is to carry out a detailed investigation into the cost of home insurance when it comes up for annual renewal.

It said it wanted to understand why prices were creeping up for many customers. The review will be a blueprint for studying other parts of the insurance sector, according to Jonathan Davidson, of the FCA.

The regulator will be taking over regulation of claims management companies (CMCs) from next spring.

In advance, it aims to assess whether brokers and motor insurers are inflating claims through referrals to CMCs.

'Real world solutions'

Elsewhere in the FCA's mission statement for the year are seven priority areas - many of which involve the treatment of customers by the financial services industry.

This will include pointing the spotlight on how firms charge longstanding, loyal customers who fail to switch compared with new customers such as those with savings accounts.

Christopher Woolard, from the FCA, said the regulator wanted a "real world set of solutions" that made switching as easy as possible, while those unable to do so went to a simply default option.

Pension advice - specifically firms encouraging savers to leave a defined benefit, or final-salary, deal to move to investment-based products - will come under the microscope. This follows concerns over advice given to many British Steel Pension Scheme members.

Other topical areas of work include investigating the security of customer data held by firms, and tackling money laundering.