THE chief executive of the North West Ambulance Service (NWAS) has left his post in unexplained circumstances.

It has emerged that Darren Hurrell, who joined the NHS trust in 2009, has not been working there for the past seven months.

Bob Williams, who became a paramedic in 1987, is now the acting chief executive.

NWAS bosses refused to say why Mr Hurrell had left. A spokesman said: “This is a confidential matter between the trust board and Mr Hurrell.

“Following a meeting of the board of directors on May 20, Mr Hurrell left with immediate effect. There were no patient safety issues involved.

“Bob Williams will remain acting chief executive until a permanent appointment is made.”

Mr Hurrell replaced John Burnside, who retired from the role in May 2009.

He had also held a number of director posts in the Northern and Yorkshire region.

The NWAS has a target of reaching all 999 calls within eight minutes.

In three of the last four months, that target has been missed.

In Greater Manchester, in December last year, only 69.97 per cent of calls were reached in the recommended time, and in Cheshire, Warrington and Wirral, just 69.9 per cent of patients were seen by a paramedic within eight minutes.

However, in Lancashire, the target was surpassed in all four months leading up to and including March 2013 .