Staff working in the proposed new foundation trusts could receive significantly more pay than their colleagues in the rest of the NHS.

Doctors have warned the plans could undermine the national nature of the health service.

A document published by the Department of Health reveals that foundation trusts could be able to offer staff unlimited pay increases.

In comparison, other trusts would have to adhere to strict limits spelt out in Agenda for Change - the new pay deal for health service staff currently out for consultation with unions.

The first wave of NHS foundation trusts is expected to be announced this summer.

These will be top-rated hospitals which will be given, for the first time, freedom from Whitehall control and the ability to set their own clinical and financial priorities.

Mr Milburn wants to free the top-rated NHS trusts

Under the terms of Agenda for Change, managers in Foundation Hospitals would be able to offer unlimited pay bonuses to help them recruit and retain staff if they can afford it.

The bonuses other NHS organisations could offer would be capped at 30%.

The document, published this week, states that foundation trusts will be able "to offer alternative packages of benefits of equivalent value to the standards benefits set out in this agreement".

It adds that this also includes "the ability to awards recruitment and retention premia above 30% of basic pay where that is justified".

Two-tier NHS

Ministers have dismissed claims that foundation trusts will create a two-tier health service.

They have also said they will find a way to ensure that foundation trusts do not poach staff from neighbouring hospitals.

However, they have still to outline how they hope to achieve this.

Dr George Rae, of the council of the British Medical Association, told the BBC that allowing some hospitals to pay higher rates could cause problems.

"National terms and conditions are one of the main building blocks of a truly national health service.

"Destroying this unity could undermine the principles of the NHS.

"It is likely to leave other hospitals with worsening recruitment difficulties."

Dr Evan Harris MP, Liberal Democrat health spokesman, also raised concerns.

�If Labour�s elite foundation hospitals offer unlimited pay increases, how will the Government ensure that they don�t poach staff from other hospitals that are not part of the foundation club?

�Many hospitals have been so badly affected by staff shortages that they have been denied foundation status. Allowing the best-staffed hospitals to effectively poach staff makes a bad situation even worse. "