Business and union leaders in Birmingham are to be asked where there are shortages in the labour market which immigrants could fill.

But there's no guarantee the workers they say they need will be allowed into the country, the Government's adviser on immigration warned.

The consultation will be held by the Migration Advisory Committee, which was created by Immigration Minister and Birmingham MP Liam Byrne (Lab Hodge Hill).

Its role is to determine where there is a shortage of skilled labour which immigrants are required to fill.

The committee holds its first meeting today and it is set to hold a series of roadshows, meeting employers and union leaders in cities including Birmingham, next month.

But David Metcalf, the London School of Economics academic chairing the committee, warned that employers who say they need immigrant labour will find their claims are subject to rigorous scrutiny.

Furthermore, a separate committee chaired by Mr Byrne will examine the effects of immigration on public services.

In principle, it could decide to limit immigration even if it leaves businesses unable to fill vacancies.

Mr Byrne's committee includes senior public service managers such as police chief constables and local education authority directors.

Prof Metcalf said: "We won't necessarily take the evidence given by employers, or anybody else, at face value. It will be vigorously and robustly analysed."