Former NHS London chief executive Dame Ruth Carnall has taken up a post as strategic adviser on health to mayor of London Boris Johnson.

Dame Ruth, who also runs a consultancy firm with former NHS London strategy, commissioning and provider development director Hannah Farrar, will begin work in the post with Mr Johnson on 1 July.

The post will initially be part-time. HSJ understands Mr Johnson is interested in working with London’s three academic health science centres and on primary care.

Dame Ruth is well known in the NHS for pushing through the centralisation of stroke and major trauma services in London at fewer hospitals.

She has been openly critical of former health secretary Andrew Lansley, saying his delay to reconfiguration schemes had affected patient care.

A document looking at the work of NHS London, released earlier this year, said the senior leadership team had worked to bypass Mr Lansley’s order to scrap the Healthcare for London plan.

Under her watch the hospital failure regime was used for the first time, on South London Healthcare Trust, which is due to be dissolved in October.

The downgrade of Chase Farm hospital in north London was finally agreed before NHS London was abolished in March and ambitious plans for the centralisation of A&E services at three fewer trusts in north west London put in place.