As we reveal this week, foundation regulator Monitor will be consulting trusts on compliance guidance to push the adoption of service-line economics (feature, page 22).

As we reveal this week, foundation regulator Monitor will be consulting trusts on compliance guidance to push the adoption of service-line economics (feature, page 22).

If the proposal goes ahead - and the arguments are strong, if controversial - it heralds a major change in the way hospital trusts think about their 'business'. And just as importantly, it promises to kickstart a clinical engagement process that has been moribund for well over a year.

Nothing sounds quite as dry and abstract as service-line economics - or specialty-level reporting, as it is sometimes called. But its potential goes to the heart of planning patient care. In simple terms it requires a trust to break down its accounts, department by department. Hence, costs, earnings and margins are revealed for the first time.

With this comes a step change in understanding the true economic position of each department and its effect on the overall health of the organisation. The three pilot trusts that the regulator has worked with suggest that clinician support is crucial, as our case study of University College London Hospitals foundation trust shows. Clever boards will want to use it as the centrepiece of their redesign strategy.

As Monitor chair Bill Moyes argues in our piece, if done successfully this can transform the way a trust negotiates with commissioners, plans its strategy and manages its risks. He argues that it will be major factor, not only in foundation trusts' success in driving up efficiency, but also in helping primary care trusts to think strategically about the implications of service redesign.

And any acute trust with an eye on foundation status, would do well to begin thinking about service-line economics in earnest as soon as possible.