A year ago Liberal Democrat members voted to demand changes to the government's proposed health reforms. At the time of their 2011 spring conference, the health and social care bill was beginning its passage through the Commons. The changes the party called for would have reduced the marketisation of the health service, controlled the introduction of competition, brought some local democratic accountability, and retained commissioning as a public sector function. The terms of the motion would still have respected the Conservative policies (for example, a greater role for GPs in commissioning) agreed in the coalition programme.

The government subsequently embarked on a "listening exercise", but those of us in the party who proposed the key amendments were very disappointed with the results. It failed to deliver most of what had been called for in respect of competition, marketisation and undemocratic structures. We went to great lengths, explaining to the party leadership and parliamentarians what the problems were. Indeed the amendments we felt were needed were all tabled by Andrew George MP, but not debated. At the party's autumn conference activists were denied the opportunity to debate another motion setting out their concerns. "Wait for the Lords to sort it out," we were told.

On Tuesday night the Lords completed the bulk of the revision of the bill. Have the concerns of the party been met? In short, no. The bill does now offer improved transparency of decision-making in commissioning, tackles conflicts of interest, and rules out price competition. But it does not deliver on local democratic accountability. And it fails to provide the required safeguards against existing NHS services being destabilised by competition. The regulator, Monitor, is partly constrained from letting competition rip. But the bill is still framed so that a market-oriented regulator (which is what Monitor's personnel are bound to be) will be free to drive competition into the health service "in the patient's interest", as there is no reciprocal requirement to promote collaboration.

The remaining problems are significant. First, the failure to hold in check Labour's own drive towards the privatisation of commissioning. This is despite the Lib Dem conference having called for planning of health services to be a public function and not hived off to the sharp suits from PwC or McKinsey with all their vested interests.

Second, after the so-called "listening exercise", the government made the bill much worse by requiring GPs to promote both choice (and thus competition) and "innovation" above tackling the deep-seated problems of unfair access to healthcare and gross disparities in health outcomes. No Liberal Democrat should support a bill with that order of priority. So while Lib Dem peers have won important concessions, especially in the area of competition law, and while the bill now contains requirements designed to preserve integrated care, it still goes well beyond the coalition agreement.

Despite the fact that this bill is designed in the image of successive Labour health secretaries, from Alan Milburn to Patricia Hewitt, the pure raw politics of health should dictate to many Liberal Democrats – and even Tories in their more sanguine moments – that this bill be ditched. It has no friends among even the non-party-political royal colleges, and has no mandate in those areas where it goes beyond the coalition agreement. The political impact will be to retoxify the Tory brand – which they are welcome to do, of course –, but also, by association, to damage the Lib Dems.

Some damage is a logical consequence of a deal that involves deficit reduction. But this bill adds extra unnecessary political pain. Unless there are more last-minute changes to deliver what the party required, at this weekend's party conference I urge Lib Dems to call for the plug to be pulled on this legislation – for the sake of the NHS.

• Dr Evan Harris is vice chair of the Lib Dems' federal policy committee. He has written a full analysis on his Guardian political science blog