They are adapting methods of studying ocean life to identify anonymous text authors by their spelling, grammar and syntax of words used.

Analysis of text messages sent from Ms Nicholl's phone showed they were more likely to have been written by murder suspect David Hodgson.

Looking at character abbreviation, Ms Nicholl regularly wrote "I am" and "myself" in text messages, but after her disappearance, these words changed to "im" and "meself", common features of Hodgson's text writing.

Tim Grant, deputy director of the Centre for Forensic Linguistics at Aston University, sought the help of ecologists who differentiate between marine environments by seeing how close or far apart they are in terms of species.

Applying the same statistical method to text messages can show how close or distant different extracts of writing are.

Dr Grant said: "We can measure similarity and difference by means of the stylistic distance between any two text messages.