A toxicologist from Leeds University has played down claims from Labour's shadow environment secretary Mary Creagh that the drug phenylbutazone causes cancer in humans.
Professor Alistair Hay said there is "no convincing evidence of carcinogenicity".
More top news
Nigel Farage warned on Friday Britain was "far less safe" and exposed to Cologne-style sex attacks because of open-door immigration.
Arthur Simpson-Kent, 48, admitted killing Ms Blake and their sons according to his lawyer.
Two brothers have been arrested on suspicion of murder after their parents were found dead in their own home over the weekend.