Labour MPs have faced fresh calls to block government plans for NHS reform.

Unison, the largest of the health unions, has written to every Labour MP urging them to vote against the health and social care bill, which offers the best performing hospitals foundation status, giving them greater financial autonomy.

The plans have been heavily criticised by unions and MPs from all sides of the political divide.

In a vote held in July, the government narrowly avoided defeat on the issue, when 62 Labour backbenchers voted against the reforms.

The proposals were later rejected at the party's conference in Bournemouth.

The health and social care bill enters the Lords this week where it is expected to face considerable opposition.

However, Unison is seeking to block the reforms when they return to the Commons.

"It will lead to some hospitals gaining at the expense of others, creating competition where there should be cooperation and adding to the creation of a market for healthcare delivery," said general secretary Dave Prentis.

"Despite all the government rhetoric about local accountability, foundation hospitals are quite clearly being introduced regardless of whether they have the support of local communities, patients or staff."