Charles Howeson, who has been chairman of the Rowe Group and Coutts and Co, head of the NHS for the South West and chairman of First Great Western Advisory Board, had been expected to add his name to the list of candidates for the May poll.

However, he has now announced he will not stand to replace PCC Tony Hogg but will support independent former assistant chief constable Bob Spencer.

In backing the Spencer campaign, Mr Howeson becomes the latest high-profile figure to attack the politicisation of the role, which holds to account the police force in Devon and Cornwall.

Conservative candidate Alison Hernandez, who is chief of staff for Torbay MP Kevin Foster, has openly spoken of her intention to use her political clout if she is elected.

But UKIP candidate and retired police constable Jonathan Smith has pledged to campaign to scrap the role if elected.

He joins fellow candidate and former Devon Lib Dem MP Richard Younger-Ross who has thrown his hat in the ring with a similar pledge to try to abolish the post while in office.

Now it has emerged that another proposed candidate, former police officer Simon Payne, says he has also decided to stand down as a candidate to act as Mr Spencer’s campaign manager.

Mr Howeson said winning the election on a political ticket will leave the new PCC with a “conflict of interest”.

But he has decided to pull out so as not to “water down” support among those who favour a non-political candidate.

“The next PCC will need, and be expected, to challenge whatever national government on behalf of the South West population impartially and this could get very tough indeed,” he added.

“There will be no room for coziness or any lack of resolution. So however good they might be as individuals, if they had been party politically placed, our next PCC would almost certainly have to grossly embarrass their sponsor, simply in order to do their job right for us! And just how likely is that?

“For this reason I believe that only an entirely non-party political candidate can satisfy the local remit, however outstanding or well-motivated any individual political appointee may be.”

Mr Spencer said he was delighted to have the backing of Mr Howeson, who commands support among businesses in the two counties.

“Charles has unparalleled links with, and influence within, the peninsula’s wider business community, as well as nationally,” Mr Spencer added.

“His own strictly non-party political balance, strategic experience and perspective on the challenges that we all face in the next four years will perfectly complement my own and so be invaluable.”

Mr Payne added: “After meeting with Bob and talking about our shared views and values, I felt I wanted to support Bob’s campaign and could best do this by being his campaign manager.”