KPMG chairman Simon Collins described the result as ushering in a new era for business, saying: ‘Companies are concerned and need time to assess the implications. But businesses are resilient and will adapt to any new landscape.’

David Sproul, chief executive of Deloitte UK, said: ‘While the UK has opted for a future outside the EU, Britain remains a competitive, innovative and highly-skilled economy and an attractive place for business.  However, as indicated by today’s market volatility we are likely to see a period of uncertainty.  

‘Businesses need to ensure they are set up to navigate the immediate risks and impacts of an exit, and have the processes and people in place to manage a period of upheaval. Against this backdrop of uncertainty, British businesses must continue to be proactive in finding ways to raise productivity and drive growth.’

This view was echoed by Robert Hannah, chief operating officer at Grant Thornton UK, who said there was now likely to be a period of ‘instability and uncertainty’.

‘It is important to bear in mind that very little changes immediately, so businesses should stay calm, review their contingency plans and start considering the mid-long term opportunities while the dust settles. Organisations need to assess the risks to their business and develop strategies which mitigate these, or indeed, capitalise on new opportunities,’ Hannah said.

Carolyn Fairbairn, CBI director-general, said: ‘Many businesses will be concerned and need time to assess the implications. But they are used to dealing with challenge and change and we should be confident they will adapt.

‘The urgent priority now is to reassure the markets. We need strong and calm leadership from the government, working with the Bank of England, to shore up confidence and stability in the economy.’

Kevin Nicholson, head of tax at PwC, said that Brexit will undoubtedly affect how people and businesses are taxed, and in the short term predicted that uncertainty on future tax rules will create challenges for businesses as they plan ahead.

‘The UK will now have more scope to use tax to help particular industries, regions, and groups of people. Great care will be needed to prevent unintended consequences as legislation from Brussels is removed. Longer term, there will be fewer layers of legislation, which should simplify the tax system for businesses large and small,’ he said.

Nicholson pointed out that from the date of exit, the UK will have much greater freedom to set its own VAT rules, which could see more items being zero rated, or could be used as a way of increasing tax revenues. He also said the future shape of corporate tax in the UK will change, although it is not possible to predict exactly how.

Nicholson said: ‘EU directives and EU case law will not be relevant to UK corporation tax. This may reduce the amount of legislation but, as this includes legislation which act as relieving provisions, in some cases business will end up paying more tax.

‘For example, the zero rate of dividend withholding tax under the parent-subsidiary directive will not apply and UK parent companies will need to fall back on treaty rates of withholding – which in the case of Germany and Italy are higher.

‘The UK government will also no longer need to ensure that corporation tax legislation permits freedom of establishment in other EU member states. Depending on the exit negotiations, it may feel freer to implement measures to attract foreign investment as part of the “Britain open for business” initiative.’

In its analysis of developments post-Brexit, ICAS said there will issues raised in other areas of government policy, including anti-money laundering, data protection, competition, harmonisation of product standards, consumer rights, and pensions.

ICAS said in a statement: ‘In areas of accountancy, what new policies will follow? Will it be inclined or persuaded to depart from International Financial Reporting Standards (IFRS) and re-establish UK generally accepted accounting practice (UK GAAP)?  Will the EU audit directive and regulations continue to be implemented as planned, or will some aspects be reversed?’