Lawyers fighting to free the Yorkshire Ripper, Peter Sutcliffe, have not ruled out appealing against a High Court decision to keep him locked up for the rest of his life.

High Court judge Mr Justice Mitting yesterday ruled that the Bradford lorry driver, who murdered 13 women and attempted to murder seven others, will end his days behind bars.

The judge, sitting in London, said he had read statements from relatives of six of the murder victims of Sutcliffe, now 64, who has changed his name to Coonan, his mother’s maiden name.

He said: “None of them suggest any term other than a whole life term would be regarded by them as appropriate.”

Explaining his ruling he said: “This was a campaign of murder which terrorised the population of a large part of Yorkshire for several years.

“The only explanation for it, on the jury’s verdict, was anger, hatred and obsession.

“Apart from a terrorist outrage, it is difficult to conceive of circumstances in which one man could account for so many victims.

“Those circumstances alone make it appropriate to set a whole life term.”

His decision was welcomed by relatives of murder victims, survivors and MPs.

But Sutcliffe’s lawyers, London-based Bindmans, have not discounted appealing the minimum term being set as a whole life tariff.

A spokesman told the Telegraph & Argus: “We could possibly appeal it. That decision has not been made, but if the client wanted to do it and we felt it was worthwhile, it might be possible.”

The law firm said the ruling also raised issues of wider significance for mentally-ill patients.

Bindmans said the only significant legal issue in the tariff-setting exercise of the case was whether the judge should admit evidence that the Respondent (Sutcliffe) was suffering from a mental disorder that lowered his degree of culpability for the offences, albeit not sufficient for the defence of diminished responsibility, and whether the mental disorder mitigated the seriousness of the offence to the extent that a lower term was appropriate.

But the judge ruled against the Respondent on that important legal point.

Sutcliffe was convicted in 1981 of the multiple murders. He was sentenced to life imprisonment, but no minimum term was set. He was transferred to Broadmoor top security hospital in 1984, after he was diagnosed with paranoid schizophrenia, and has been detained there since.

Justice Mitting’s judgement said Sutcliffe had been assaulted three times, two of them serious, at Broadmoor and he had been blinded in his right eye in one of them.

Bindmans said the judgement said he had been well-behaved and had posed no threat to other inmates.

In the opinion of his treating doctor, Kevin Murray, he suffered from a chronic treatable mental illness for which he had been willing to accept appropriate treatment and had been successfully contained for many years.

Sutcliffe’s younger brother, Mick, 59, of Bingley, declined to talk about the judge’s ruling yesterday.

But previously he has said that he could never see his brother being released, although Sutcliffe had given him the impression he hoped to get out one day.

Mick Sutcliffe had said then: “It is something he would want eventually, whenever it was. But he is not expecting to be released and if it was in another 20 years his life would be gone anyway.”

Police sources said unsolved cases, which might have been linked to the Ripper in the past, would still be considered but the High Court ruling did not alter the attitude of police.

One officer said: “Undetected cases are kept under constant review and this does not change anything in respect of that. It does not mean new cases are going to come out of the woodwork, but it will be business as usual in terms of reviewing unsolved ones.”

Prosecuting authorities were keeping tight-lipped about the ruling yesterday.

A Ministry of Justice spokesman said: “Sentencing is a matter for the courts. We don’t comment on individuals.”

West Yorkshire Police declined to comment.