The president of European Commission said that this is the clear indication of battle with brussels over the proposed changes .
The Prime Minister plans to cut the level of migration from the EU by limiting the number of new national insurance numbers available to low skilled immigrants.
Newcomers to UK would be given temprary national insurance numbers to stop moving people to Uk for work and claim benefits indefinitely.
However Mr Barroso has already suggested that the plans would be illegal under European law.
The cap on national insurance numbers for migrants is likely to be one of a series of “red lines” which will form the basis of The Prime Minister’s planned renegotiation of Britain’s relationship with the EU.
The cap will be set to ensure that net migration falls to below 100,000 from 250,000, The Sunday Times reported.