The Royal College of Nursing is urging MPs to back the suspension of large-scale private finance initiative schemes, pending a 'robust independent evaluation'.

The call marks a watershed for the union, which general secretary Beverly Malone admitted in July did not have a clear position on the private sector's role in the NHS, and brings it closer to public service union Unison, which is also calling for a PFI moratorium.

The RCN's harder line comes in written evidence to the Commons health committee's inquiry into the private sector's role in the NHS. It will add to pressure on health secretary Alan Milburn, who was set to defend the government's position at the committee's first hearing on Wednesday.

Written evidence jointly submitted by the NHS Alliance and the King's Fund cautions primary care trusts to 'experiment carefully'with public-private partnerships. Its paper says LIFT, the PPP scheme aimed at improving primary care facilities, 'does not make it clear how value for money is to be defined'.

'In particular, it does not specify that there must be a public sector comparator. Instead, the LIFT company, once formed, appears set to enjoy a local monopoly of health service development.'

Meanwhile, contractors'body the Business Services Association has submitted its proposals for tackling the 'two-tier workforce' - where support staff transferred to contractors from the NHS and 'new starters'with the private firm are on different pay and conditions.

BSA director general Norman Rose said: 'We propose to pay new starters a broadly equivalent package, looking at the overall package for public sector workers.' But this did not mean contractors being tied into Whitley rates, he stressed.