The departure of significant numbers of migrant workers would leave Britain with a deep skills gap, according to a member of the Trades Union Congress (TUC).

A spokesman for the organisation claimed the arrival of immigrants is often an indicator of a strong economy and expressed concern over home secretary Theresa May's plans to introduce a non-EU migration cap.

"If large numbers of workers leave the UK, the economy will be left with damaging skills shortages," he claimed. "This shows just how important it is for both the government and employers to invest in skills."

The representative warned that taking action to restrict the flow of labour – combined with the continuing departure of expat workers – into Britain could hamper the fledgling economic recovery.

His comments came after HSBC's latest Expat Explorer Survey found 67 per cent of British expatriates quizzed thought the country's financial strength had deteriorated since the start of last year.