The election for Wiltshire and Swindon police and crime commissioner may need to be re-run after the race was won by a candidate who withdrew over a historic driving conviction.

Conservative Party candidate Jonathon Seed received 40% of the vote in the first round and was elected after it went to a second ballot, but will not be able to take up the post.

In a statement released after the result was declared, the election’s returning officer Terence Herbert said he would be considering the next steps after taking appropriate legal advice.

Mr Herbert said: “The election has been called and Jonathon Seed has been duly elected.

“As regards to the next steps, as the head of paid services, I am the appropriate officer for making any declaration as to the Office of the Police and Crime Commissioner becoming vacant.

If the post of the PCC is vacant, if someone is disqualified or does not sign the declaration, then the post will be defined as vacant and an election will be called

“Given this unprecedented situation and given the circumstances, I will be seeking legal advice on the next steps and at that point I will be able to make any statements necessary about the position.

“If the post of the PCC is vacant, if someone is disqualified or does not sign the declaration, then the post will be defined as vacant and an election will be called.”

A Conservative Party spokesperson said Mr Seed, who had been hoping to take over from departing Conservative colleague Angus Macpherson, had been “disbarred” after a driving offence had “come to light”.

In a statement issued on Sunday, Mr Seed – who won a combined total of 47% of the vote – insisted he had declared his conviction to the party in his application for the role.

Mr Seed said: “To the best of my knowledge and belief when I applied for, and became, the police and crime commissioner candidate for the Conservative Party in Wiltshire and Swindon, I was an eligible candidate.

“I have declared my 30-year-old driving conviction to the party in my applications both to be a parliamentary candidate and more recently a PCC candidate.

“Party officials confirmed my belief that my offence did not disqualify me. I have now been advised that this is not the case, and that I am disqualified as a PCC candidate. I have therefore withdrawn.”

Mr Seed – who won a total of 100,003 votes – added he would be “bitterly disappointed” not to take up the post if he won the election.

Electoral Commission guidance says PCC candidates cannot stand for election if they have been convicted of an offence punishable with a prison sentence.

Liberal Democrat candidate Liz Webster, who came second after securing 17% of the vote in the first round and a combined total of 27%, said: “The question that needs to be asked is when the Conservative Party knew (Mr Seed) was ineligible to stand and, if that was before Thursday (polling day), why they didn’t say anything, because voters could have made an informed decision.

“It’s going to cost the taxpayer £1.4 million to re-run the election, and there will obviously have to be a further police inquiry and, depending on the outcome, it may be a case for the Crown Prosecution Service.”

Ms Webster, who won a total of 58,074 votes, added: “Jonathon Seed has treated Wiltshire and Swindon residents with total contempt.

“Re-running this election will require residents to vote again and deny our tired elections staff their well-deserved break. All of that is an absolute disgrace.”

A spokesperson for the Office of the Police and Crime Commissioner (OPCC) said: “While this situation is unprecedented, there is legislation in place for this eventuality and due process will be followed.

“Angus Macpherson remains as police and crime commissioner until Thursday.

“The OPCC will be working closely with Wiltshire Council, Swindon Borough Council and the Police and Crime Panel, once confirmed, to ensure any following legal process is handled as effectively and efficiently as possible.”

Mr Seed – who faced competition from five other candidates for the PCC post which involves holding Wiltshire Police to account, overseeing a budget and setting its priorities – was also re-elected as a councillor to Wiltshire Council for the Melksham Without West & Rural ward on Saturday.