Britain's most intriguing murder mystery, the identity of Jack the Ripper, has had as many suspects and red herrings as any Agatha Christie story. But one of Britain's leading forensic handwriting experts, Derek Davis, is prepared to stake his reputation that the Ripper was, in fact, a Scottish born Doctor, Thomas Neill Cream.

Independent evidence comes from a Canadian author and journalist, Donald Bell, who is planning a book, Dr. Ripper and Mr. Cream, for 1988, the centenary of London's East End terror.

Mr. Davis has impeccable credentials for the task of unmasking the Ripper's disguised handwriting. He has acted on behalf of all the joint stock banks in England, the Office Solicitor, Lloyds, and professional bodies like the Law Society and General Medical Council.

Now he has re-examined for The Times evidence from letters which appeared in The Criminologist, a forensic journal, 10 years ago. They convince Mr. Davis that Cream was the Ripper.

One, to Mr. George Lusk, chairman of the Whitechapel Vigilance Committee, was assumed to have been sent by the Ripper. Another was thought to be a hoax, though signed Jack the Ripper. The others were known to be by Cream.

Mr. Davis first shows that the letter to Mr. Lusk and the one signed Jack the Ripper were, although heavily disguised, written by the same person.

The letter to Mr. Lusk showed evidence of a natural slant to the left. The one signed Jack the Ripper and presumably written in a style to confuse, has a slant to the right, but the writer could not be consistent. More evidence of deliberate disguise comes from the spelling. In the two letters the spelling of "kidney" is correct once yet wrong twice: "kidny" and "kidne", while more difficult words like "half" and "guess" are correct.

The word "and" is a giveaway. It is out of pattern with the rest of the Ripper's handwriting and more in pattern with that of Cream's. The disguise has slipped. Similarly, cream's final stroke in characters like "m," "n" and "d" curl upwards.

The upward stroke beginning the first letter of a word is another telltale sign. Cream tries to remember to omit the initial movement - natural to him - in the letters to Mr. Lusk and from Jack the Ripper but fails. His disguise of his natural "r" cannot be kept up either.

Mr. Bell backs up the evidence from a different angle. In an interview he says George Hutchinson, a labourer, followed the Ripper's last victim the night she was killed. Hutchinson saw her accompanied by a man to the place where she lived. The description resembles Cream's: a moustache turned up at the ends and dark complexion; 34 to 35 years old; about 5ft 6in tall. The man's black tie had a horseshoe tie pin. Cream also wore one.

Mr. Bell meets head on two of the main objections to Dr. Cream being the Ripper. The first is that Cream was a poisoner. He was hanged for it. But eye witnesses said that on the gallows Cream's final words were cut short: "I am Jack..."

The second objection is that Cream was supposed to have been serving life imprisonment in Joliet (Illinois) in 1888 when the Ripper was killing and mutilating his victims. But prisoner sometimes paid to have substitutes in jail, Mr. Bell says.

Peter Evans.