Britain could face a serious shortage of skilled workers after Brexit, with almost half of European Union citizens working in the UK said to be ready to leave the country over the next two years.

According to a Deloitte study on the impact Brexit will have on the UK's jobs market, 36% of non-British workers are reportedly considering leaving Britain after it exits the EU by March 2019. The figure amounts to 1.2 million of the 3.4 million of non-British workers in the UK.

The percentage, however, rises dramatically among highly-skilled EU workers, with 47% of them said to be mulling the prospect of leaving the UK within the next five years. Meanwhile, 26% of non-British workers said they could leave within the three years.

The report, Deloitte said, is a major warning to the government, which has previously come under pressure to ensure employers do not face a skills shortage following Britain's exit from the EU.

Since the Brexit referendum last year, a number of studies have highlighted EU workers could consider leaving the UK or have already done so. Post-Brexit uncertainty, both in terms of financial prospects and citizen's rights, and the pound's sharp decline have been mentioned as the main motivating factors.

Sterling has lost 13% of its value over the last 12 months, meaning pound-denominated salaries are now worth less in euros for EU workers who send money back to their home countries.

However, the survey of 2,242 EU and non-EU workers, half living in the UK and half living outside, also found Britain retained some of its appeal as a place to work. Some 57% of respondents based outside Britain placed Britain in their top three destinations, ahead the US, Australia and Canada.

The percentage, however, declined to 48% among workers already living in Britain, who claimed the country had lost some of its appeal since the referendum, an opinion shared by 21% of respondents based outside the UK.

"The UK's cultural diversity, employment opportunities and quality of life are assets that continue to attract the world's best and brightest people," said David Sproul, chief executive of Deloitte north-west Europe.

"But overseas workers, especially those from the EU, tell us they are more likely to leave the UK than before. That points to a short- to medium-term skills deficit that can be met in part by upskilling our domestic workforce but which would also benefit from an immigration system that is attuned to the needs of the economy."

Published on Tuesday (27 June), the study comes only a day after Theresa May outlined to the EU her plans on the rights of EU citizens leaving in Britain. Making what she described as a "fair and serious offer", the Prime Minister said EU citizens already living in the UK and those who arrive legally during a two-year "grace period" after March 2019 will be given the opportunity to build up five years' worth of residence.

That would then allow then to become apply for "settled status" in the UK, which would confer them all the rights of a British citizens in terms of work, pensions, NHS care and other public services. May added EU citizens already in possession of a permanent residency card will have to reapply, though she stressed she aimed to make the process as "streamlined as possible".