Britain is the country most worried about mass immigration, a survey of 25 major nations reveals today.

The study by Ipsos MORI found more than 42 per cent of Britons put immigration in the list of issues which most concerns them.

By contrast, it did not figure in the global list of top five worries.

The findings are likely to prove helpful to Theresa May in her Brexit negotiations – emphasising the fact that one of the major reasons Britain voted Out was to regain control of our borders.

The poll findings are likely to help Theresa May, pictured in Spain today with her counterpart Mariano Rajoy, make the case Britain should have stronger immigration controls

They also come at a time when big business is putting pressure on the government not to impose tough new restriction on EU immigration.

Based on the findings, business leaders and MPs arguing that Britain should continue to allow free movement of migrants in return for access to the single market are significantly out of touch with the rest of the country.

Britain’s figure of 42 per cent of people being concerned about immigration is even higher than in Germany (41 per cent) and Sweden (33 per cent) – which have been worst affected by the migration crisis.

Out of the 25 countries, Britain is also the most concerned about the rise of extremism, with 28 per cent citing this as a worry.

Also in the top five worries in the UK are healthcare (34 per cent), terrorism (31 per cent) and poverty and social inequality (29 per cent).

The economy did not figure – despite the aftermath of Project Fear and a series of warnings that the economy would suffer post-Brexit.

Britons are positive about the direction the country is headed in with 44 per cent saying they think things are going in the right direction.

This is above the global average and – crucially - the most optimistic response out of the European countries in the study.

The study by Ipsos MORI found more than 42 per cent of Britons put immigration in the list of issues which most concerns them - higher than citizens in 24 other countries

Ipsos MORI managing director Bobby Duffy said: ‘Britain is most worried about immigration from all 25 countries included in the study - showing that the concern very clearly flagged in the EU Referendum has not subsided.

‘But it’s also striking how quickly initial fears that we’re heading in the wrong direction following Brexit have abated: people have not seen much impact on the economy or felt it on their own standard of living.

Institute of Directors spokesman Seamus Nevin called on Mrs May to to abandon the Government’s commitment to reduce net migration to the ‘tens of thousands’

'Whether this will continue is a matter of fierce debate, but given the importance of consumer confidence to the economy, this is at least a positive.

‘This relatively relaxed economic view is backed up by comparing our worries with other countries. In particular, unemployment is the top global concern – but it doesn’t even feature in the top 5 in Britain. Countries like Spain and Italy are in a completely different place, with around 7 in 10 people saying unemployment is a key worry.’

The poll is setback to big business in its demands for continued mass immigration.

The pro-Brussels CBI lobby group claims that continued access to low-skilled EU migrants is vital for the economy.

Today, the Institute of Directors calls on Theresa May to abandon the Government’s commitment to reduce net migration to the ‘tens of thousands’.

The IoD is also urging ministers to announce that any EU migrant already living and working in the UK should be allowed to stay.

IoD spokesman Seamus Nevin said: ‘The Leave majority was, in part, a vote of no confidence in how successive governments have managed immigration.

'Dissatisfaction with policymakers was exacerbated by the Government under-delivering on a promise to bring the number of migrants down to ‘tens of thousands’. The persistence with this target is hard to understand, and we beg the Home Secretary to think again.

‘Those who voted to leave the EU did so for many reasons, but we don’t think anyone wanted to make the country worse-off.

'The evidence is very strong that immigrants play a positive role in our economy, but the Government needs to tackle the public’s concerns, without hindering the nation’s prosperity in uncertain times.’

Mrs May has indicated she will resist the demands – re-stating her commitment to tens of thousands.

She has also pledged that restoring full control of the UK’s borders will be her priority in the Brexit talks.