There's no evidence for it. However, I don't think entertaining the possibility that the timing of the attack was determined by a significant public event in the UK amounts to endorsing any kind of conspiracy theory.
The conspiracy theory being entertained is this.
The conspirators are those whose interests are served by withholding information from the public.
The conspiracy theory being entertained is this.
The conspirators are those whose interests are served by withholding information from the public.
The conspired against would be the public.