KEY evidence in the Stephen Lawrence murder was missed by the original forensic scientists because they did not look for it, the Old Bailey has heard.

Gary Dobson and David Norris are on trial for the 1993 murder based on scientific evidence unearthed in a 2007 cold case investigation.

But back in 1993, when Met Police forensic scientists first examined clothing from Mr Lawrence and the suspects, techniques were different to those used more recently.

Adrian Wain led those investigations, assisted by Yvonne Turner.

He told the court, these were the days before DNA testing, and any examinations carried out on blood could only be done on a larger stain than today's methods require, and even then would only identify blood groupings.

Mr Wain said: "By today's standards it's a very crude tool."

He said that his strategy had been to search for blood on a limited selection of the suspects' clothing, examine fibres and look for hairs.

But crucially, the search only looked for fibres transferred from the suspect’s clothes to Mr Lawrence's outer garments during the attack, jurors heard.

Fibres from Mr Lawrence's clothing being transferred on to Dobson or Norris's garments during the murder was ruled out as a possibility early on, partly due to the brevity of the attack.

There was also no checking for fibres beneath Mr Lawrence's outer clothing, while other material was excluded from the search for being "too common".

Neither was there any examination of debris in the evidence bags where the clothes were stored, or a microscope check of the clothing for blood stains.

All these things were carried out in 2007 by scientists working for the LGC firm, providing fibres and hair, linking Norris and Dobson to the murder, jurors have heard.

But the 1993 techniques found just four fibres in all which were deemed to be of no significance, Mr Wain said.

When a re-examination was carried out in 1995 as part of the Lawrence family's private prosecution, for the first time Mr Wain looked at possible transfer of fibres from Mr Lawrence's clothing to those of the suspects.

But even this only led to four more fibres being discovered, providing weak or very weak evidence, Mr Wain said.

Prosecutor Mark Ellison asked him: "Is there anything that LGC found later on that, if it had been in 1993, 1994 or 1995 you would say you'd have found?"

Mr Wain said: "I wouldn't have found it because I didn't look for it. That's the simple answer."

Dobson, aged 36, and Norris, aged 35, both of south London, deny murder, claiming the evidence against them has been contaminated.

The trial continues.