A lawyer for the police said he was worried about "sensationalising" the inquest with a live demonstration of the bag and offers a video clip by an expert as alternative.
Police reveal "problems in the DNA analysis" of mixed profile found on Williams' hand - found the contamination was from scientist at scene.
The error was spotted by a scientist who's evidence helped convict the killers of Stephen Lawrence in January. The coroner wants to hear from her.
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Industrial vacuum cleaners and magnetic wands will be used each night during the summer to remove metal particles, dust, oil and grease.
Detective Superintendent Fiona McCormack said the Hotpoint FF175BP model had not been subject to any product recall.
Security for this year's event on July 8 has been reviewed following a spate of terror attacks in the capital.