THE British coalition has had its first major row in public with the Liberal Democrats accusing the Prime Minster, David Cameron, of stoking racial tensions with an ''inflammatory'' discourse on immigration.

The speech, which contained a pledge to slash immigration numbers from hundreds of thousands to tens of thousands, and blamed a ''woeful welfare system'' for discouraging Britons to work, was described by the Business Secretary, Vince Cable, as ''Tory policy only'' and ''not part of the coalition agreement''.

And despite assurances that the speech had been seen before its delivery by his Liberal Democrat leader, Nick Clegg, Dr Cable also dismissed the speech as ''very unwise'' and ''inflammatory''.

''I do understand there is an election coming,'' he told the BBC, ''but talk of mass immigration risks inflaming the extremism to which he and I are both strongly opposed.''

The speech was the first major statement delivered by Mr Cameron in the run-up to next month's local elections.

It was delivered at a moment in Europe when many communities, including Britain, France Germany, Italy and Spain, are trying to cope with the tough austerity measures imposed after the credit crunch.

Insecurity over unemployment is rife and tension over immigration - particularly with news bulletins carrying images of the exodus of refugees from Maghreb countries, such as Libya and Tunisia - is creating further anxiety.

Mr Cameron insisted his speech had not only been seen by Mr Clegg but that the cuts to numbers were the result of ''robust discussions'' within a cabinet subcommittee and agreed by both parties.

Mr Clegg did not comment yesterday and his spokesman said only that the speech had been ''noted'' not approved.

Mr Cameron called for ''good immigration'' not ''mass immigration'' saying that Britain's population has increased by 2.2 million between 1997 and 2009 in what he described as the ''biggest influx'' in recent years.

However, he also found himself in the embarrassing position of having harnessed the public support of the British National Party, which even accused him of stealing its policies.

''It's cynical opportunism, isn't it? It's almost like a ceremonial adoption of our policy about two weeks before any major vote.'' said a BNP spokesman.

Significantly, the timing of the speech also sits in the run up to next month's referendum on whether Britain moves from a first-past-the-post voting system to one where voters can rank candidates in order of preference.

Some Conservatives argue that their chances of pushing a ''no'' to the proposed ''alternative voting'' system will rise if lower-middle-class voters, who have been hard hit by the economic crisis, turn up and exercise their vote.

Dr Cable, however, insists that continued migration from outside the EU is critical to fostering economic growth. But his intervention may also stem from a desire to reharness support lost from diehard Liberal Democrats who remain incensed by the Leftist party's decision to join the Conservatives in government.