Keith Vaz, prospective parliamentary candidate for Leicester East, is a keen user of Twitter. On any given day, the veteran MP, who has held the constituency for the Labour party since 1987, can tweet half a dozen times or more, spraying a mix of feeble self-promotion and blunt political rhetoric. Except at the moment. Last Sunday, he tweeted his thanks to the Bollywood star Abhishek Bachchan, who had visited the city to campaign alongside him. Since then, Vaz has been uncharacteristically silent.

It’s bizarre, because finally there’s something people want to hear him talk about. Last week in the Observer, I described how my 1991 investigations into allegations of child sex abuse by the former Leicester MP Greville, now Lord, Janner, were brought to a halt by supportive statements in the Commons from MPs. Key among them was that by Vaz, who said that his close colleague had been “the victim of a cowardly and wicked attack”.

When news first broke on 16 April that Janner would not stand trial on 22 counts of child abuse because of his dementia, I asked Vaz via Twitter whether he would care to comment about his support for Janner. He first reacted by blocking me. He unblocked me, but didn’t respond.

I assumed that he would speak after my article was published and widely circulated, but no. A week on, and the failure to respond properly to the issues I have raised continues.

The most generous analysis is that Vaz is making a blunt political calculation in the midst of an election: he just has to tough it out. The problem is that the longer he fails to address the issues fully, the more complicit he seems in a passive establishment effort to help Janner to avoid facing charges in court.

It’s not as if there isn’t a form of words he could use. He could reference the recognised cleverness of suspected abusers, and express regret if anything he once said added to the distress of Janner’s alleged victims. It seems he has decided against that. As a result, a matter that could have been consigned to history remains very much alive.