One of the original Labour Party rebels from the 1980s, Lord Owen, has sided with his old party to thwart the coalition government's health reforms.
A leaked email from Owen and obtained by the Telegraph outlines a number of key amendments to NHS legislation that he would support, while claiming a campaign on health by the party would be beneficial if it should become the government "on a loss of confidence motion in 2013".
"The truth is that the NHS is now seen by the country as a major dividing line between the Labour Party and that of the Conservative Party and, surprisingly, the Liberal Democrats," read the email sent to Labour spokesmen, including Baroness Thornton and Lord Beecham, in October.
"While you have to attract Liberal Democrat MPs if you are to win a vote of no confidence this side of a 2015 general election, that is not the same as attracting Liberal Democrats in the House of Lords. I will help in committee but think it better if you put down the amendments.
"I suggest you need four absolute red line amendments from which you do not move and which you promise to implement urgently as soon as you return to government," Owen added.
He went on to call for Labour to support the deletion of clause 4 in the NHS reform bill, known as the "hands-off clause", which was designed to give autonomy to commissioning groups, though campaigners have claimed it would allow health secretary Andrew Lansley to sidestep political accountability.
"If Labour can get it right, it could serve to establish the NHS, like the French railways, as able to stop the EU coming into every aspect of the NHS in relation to competition and procurement policy," he said.
Owen, a Labour Party member before he left in 1981 to help found the Social Democratic Party, claims a strong position on key amendments will serve Labour well in a general election in 2015.
"If Labour is to effectively campaign on 'Saving the NHS'," Owen's email continued, "you have to be clear what you are saving and have the determination to legislate in a very short bill in a matter of months."
He warned against the danger of thinking in terms of another piece of major legislation, arguing that neither the electorate not the NHS staff want more reorganisation.
"They need to know where the sharpness of the differences are and what Labour are going to do about it. Eschew like the plague any further organisational upheaval," he added.
Owen, who is due to chair a parliamentary meeting of the Royal Colleges, has been an outspoken critic of the coalition's reforms, which would see the transfer of commissioning responsibilities pass to GPs.
Speaking in the House of Lords in October 2011 as the chamber read through the Health and Social Care Bill, Owen called for a select committee to look into health reforms, warning that "if we get it wrong, we'll be in very serious trouble".
He urged fellow members to "cherish the fact that the NHS is one of the most popular institutions in our country [and] look hard at how we can retain that".
Critics have claimed that the email shows Owen using the NHS issue for purely political means, rather than through genuine concern over the proposed reforms.