Foreign affairs and defence are the issues of greatest concern to voters, according to a poll for Friday's FT.

Marking a clear shift in voters' priorities, some 38 per cent cited international affairs as an important issue - up from two per cent in 1997 and 2001.

Over that period the NHS has slipped in the nation's priorities, dropping from 58 per cent at the last election to 34 per cent now.

Immigration and crime, however, have risen significantly up the political agenda, the MORI survey suggests.

Despite the shift, the Liberal Democrats have failed to capitalise on the Iraq issue.

The party has slipped three points to 21 per cent, with the Tories on 32 per cent and Labour on 36 per cent.