The inquest is hearing from the Detective Inspector from the Standards Department at the Met Police who says there is no evidence to back any of the claims.
The Professional Standards Detective tells the inquest jury that when the anonymous letter was sent for forensic examination, DNA was found on envelope. Billion to one chance DNA belonged to the unnamed defendant, jury is told.
More top news
Before the final declaration on Friday, the Conservative candidate looked set to lose the City Hall race to Labour's Sadiq Khan.
The Tooting MP has been the frontrunner in the counting process ahead of Tory challenger Zac Goldsmith.
It's not just London where elections have been taking place today. There were council elections taking place across the home counties.