From Marks & Spencer to Alliance & Leicester, throughout history, company mergers have created great institutions.
But where PMS and GMS contracts are concerned, the prevailing feeling seems to be 'ne'er the twain shall meet'.
Although the DoH's NHS Plan in 2000 set a target of 2004 for PMS and GMS 'to operate with a single contractual framework that will meet the key principles and requirements of a modern NHS', there seemed to be a change of heart when the GMS contract came in during 2004.
Last week, the DoH said that if PMS practices were not as cost-effective as GMS, PCTs should consider ending their contracts immediately. So does PMS have a future as an independent entity?
It appears that the DoH is certainly reviewing PMS's future. January's primary care White Paper said that the DoH would 'undertake a fundamental review of the financial arrangements for the 40 per cent of practices on local PMS contracts' and report back early next year.
Last week's guidance stated that its specific aim was to 'constrain costs of PMS contracts' in line with GMS.
A covering letter with the guidance from DoH head of primary care contracting Richard Armstrong asks PCTs and SHAs to 'secure similar benefits to those achieved through the GMS contract for 2006/07, from PMS'.
The merger that the National Association of Primary Care (NAPC) said 'must not be allowed' in 2003 looks ominously close in 2006. Dr James Kingsland, NAPC chairman and one of the DoH's original advisers on PMS, still believes that PMS and GMS must not merge.
He said: 'If PMS hasn't got a future, you have to question whether there really is an agenda for choice at all. This goes right to the core of government policy, not just health, but education and other areas as well.
'PMS has a specific role in delivering choice and cannot be delivered by a national contract. A merger of the two would be very disappointing.'
Dr Kingsland accepts that there is 'no harm' in reviewing PMS contracts and whether they are still offering value for money, but thinks that to change or cancel them on grounds of finance alone would be wrong.
He asked: 'If you rein them in for money alone, why were they commissioned? It can only be justified in the unlikely event that PCTs made incorrect calculations in the first place.'
Chris Town, one of the government's leads in negotiating GMS contracts, believes that there is little to choose between the two types of contract any more, but also says that PMS has a strong future as a separate entity.
'In many cases, you could hardly put a fag paper between a PMS contract and a GMS contract,' Mr Town said. 'But PMS contracts work well to allow PCTs to introduce local flexibilities. When the GMS contract was first established, it was expressly stated that the two options should keep running separately.
'It makes sense to make some adjustments to PMS and the fall-back position was always GMS, but the bottom line is that you can't put everyone on a simple GMS contract.'
PMS GPs on the ground are not surprised by the government's actions, saying that PCTs scrutinise them less than GMS practices, despite apparently paying them more. 'We as GPs will need to prove ourselves,' said Dr Ian Greaves, a first-wave PMS GP from Gnossall, Staffordshire. 'PCTs have not performance- managed PMS like GMS. The guidance is a harbinger to see how PMS has gone. I suspect something like quality framework visits will begin in PMS.'
Dr Greaves added that in his area, PCTs had made data available to the public, under the Freedom of Information Act, on how much each practice was receiving per patient.
'PMS is getting more than GMS and that fact stares you in the face, so you need to say what you are buying with that money,' he said. 'If you can prove you are value for money, you are safe, but if you can't show you are doing anything different, why should you receive more?'
PMS and GMS contracts might be separated by just a 'fag paper', but how long that lasts depends on how robust the divide is.