What NHS England isn’t telling you, and more indispensable insight for commissioners. This week by HSJ commissioning correspondent Sharon Brennan.

Integrated care systems are one of the first places that thoughts turned to when it was made clear by Theresa May that her government would listen to requests to change health legislation.

Yet talking to senior figures involved in the ICS agenda there is no clear agreement as to whether the centre should seek to make them (or sustainability and transformation partnerships) into statutory organisations and, if they do, what that might look like.

The indications I’ve heard are that at the centre the focus is on pragmatic small legal changes, rather than wholesale restructure, and could be made through secondary legislation, not a great repeal of Lansley’s legacy.

There remains widespread doubt about whether another top down reorganisation is feasible. Given the austere years the NHS has been through, there is likely little energy for one and the NHS has to show that the new money being pumped in will make tangible efficiencies in a shorter time period than a significant reorganisation might allow.

The centre remains clear that ICS work when they are built on trusting relationships. The dominant view is therefore that any legislative change should allow an ICS to be an option for regions rather than be forced upon the whole country in one sweep.

At a meeting of ICS leaders shortly after Theresa May made the legislation announcement, I’m told that those in the room were ambivalent about bringing in new laws. The feeling was that there was still work to be done to better integrate care across these 10 leading health economies (plus the four new ones only recently announced), which they did not need legislation to achieve.

However, there are clear potential benefits to making ICS official.

It would make it easier for them to actually employ their own staff, and it would help allay very real fears about the governance of health systems. There is growing noise from some of the 10 that the non-executives and lay people on their boards are concerned about the workarounds being employed to make ICS work when the individual statutory obligations of each separate organisation have not shifted.

Options for small changes were considered at the centre before the 2017 general election, when it also looked like the chance of legislation might open up. These may still be relevant. They included ways of ensuring provider trusts are also compelled to work for the good of the health system as a whole; and enabling easier delegation and pooling of responsibilities between existing organisations, by adjusting the regulations governing CCGs, for example.

If NHS England is still set on ICS replacing STPs, as it announced in its planning refresh, ICS also have to work for the many – not just the few systems that already have good relationships.

Legislation could be a way to prevent a two tiered NHS where patients get better care if the leaders of the region like each other. It would also prevent ICS unravelling when system leaders inevitably move on.

For ICS, one downside of the current legislative offer is timing – the offer from the government may have come earlier than the system is quite ready for.

ICS are very new beasts that are yet to be tested on finances or population outcomes. 2018-19 will be the first year that some take on a form of system wide financial control total, an experiment which may or may not work.

A story of mine from last week also shows that the relationship with and between local authorities is put to the test in ICS, and the nature this might take in any law change is uncertain.

The other issue key to ICS development is competition law. Many of the 10 have said they are happy to delegate budgets from commissioners to NHS providers, or to award contracts, without going out to competitive tender.

Without legal change, it seems inconceivable that this can continue for much longer without challenge by an angered alternative provider.

However, if changes to procurement law may be desired in practice, this is a much thornier issue as it is tied up with EU legislation. With a Brexit agreement still not concluded, this could easily be kicked down the path.

However, the offer from the government is on the table and the NHS cannot assume it will be given this chance again. It may be decided that the timing is right because it has to be.