Colin Inglis is being investigated by North Yorkshire Police

North Yorkshire Police are already looking into claims made in September.

But the Independent Police Complaints Commission (IPCC) says that an allegation made against Mr Inglis in the 1990s should be looked at again.

Mr Inglis, also the leader of Hull City Council, told BBC News he would not resign as he had done nothing wrong.

The allegations, which have always been strenuously denied by Mr Inglis, centre on his time as a social worker at a children's home in Hull in the 1980s.

Humberside Police investigated abuse allegations against him in 1997, but the Crown Prosecution Service decided there was not enough evidence to take the case any further.

I have never hidden from this - my conscience is clear Colin Inglis, Humberside Police Authority chairman

Now the IPCC has intervened and asked for the current investigation to be broadened to include these older allegations.

A spokesman said: "The IPCC has looked at the investigation which was concluded in 1998 and decided this should be included in the remit of the current investigation."

Meanwhile, the IPCC is conducting a separate inquiry into the way Humberside Police dealt with the original allegations of sex abuse.

It is examining claims that the force failed to investigate complaints on three separate occasions.

News that the investigation is to be widened prompted Humberside Police Authority member John Neal (Liberal Democrat) to call for Mr Inglis to resign.

"Anybody in a position of authority like that should stand down pending the results of the investigation, otherwise the public will say, quite rightly, there is collusion going on," he said.

'Good answers'

Mr Inglis remained defiant when questioned after attending a Hull City Council meeting on Thursday.

"If I resigned from all my political positions all of this would go away overnight and that is the object of the exercise, quite frankly," he said.

"I don't think that is the right thing to do.

"I have never hidden from this, I have never said I will not answer any allegations made against me and I have got very good answers to anything that is said.

"My conscience is clear and always will be because I have not done anything wrong."