Midland health services are underfunded by almost £140 million, the official NHS watchdog has revealed.

The region's primary care trusts, which provide GP and dental services, get less money than they need.

However, trusts in other part of the country receive grants significantly higher than their target funding.

The figures were published by the Healthcare Commission, a statutory body responsible for inspecting NHS services.

It compared the money received by health trusts with the target budgets set by the Department of Health.

Heart of Birmingham PCT has one of the largest funding gaps in the region, and is set to receive a budget £20 million lower than its target.

The funding gap is £17.5 million for Eastern Birmingham PCT, £21.8 million for Coventry PCT, £16.5 million for Wolverhampton City PCT, £9.9 million for Telford & Wrekin PCT.

Across the West Midlands, health trusts are underfunded by £139.1 million.

The figures show the funding gaps, known officially as the Distance From Target, for 2006-7.

Target budgets were drawn up to end the " postcode lottery" which meant some health trusts got more money than others for no clear reason.

Instead, funding is now supposed to be based on the specific needs of different areas. For example, trusts in areas with a large elderly population are supposed to receive more.

But it has proved difficult to cut funding in areas which are significantly above their target budgets.

Many of these are in London. For example, Lambeth PCT is to receive £54 million above its target budget, while Westminster PCT is to receive £47 million extra. Wandsworth PCT will receive £43 million above its target, while Lewisham will receive an extra £42 million.

As a result, the money is not available for Midland trusts.

The financial position of the region's health services has been in the spotlight in recent months,

A separate report from the Healthcare Commission warned last month that 20 of the 67 health trusts in the West Midlands had gone over budget last year.

And The Birmingham Post revealed last month that Health Secretary Patricia Hewitt had written to 20 West Midland trusts showing " a significant deficit".

Trusts across the country went £500 million into the red last year.

MP Richard Taylor, a retired consultant, said: "These are large sums of money, and I am sure health trusts which are in the red would say it is a result of underfunding."

The Department of Health admitted some areas were receiving less than their fair share of funds, but said the gap was being closed.

A spokeswoman said: "For the 2006-2008 revenue allocations, it was decided to move PCTs more quickly towards their fair share of funds.

"As a result of this allocations round, no PCT will be more than 3.5 per cent below its fair share of funds by the end of 2007-8."