GLA

The monitoring officer was also asked to clarify the rules about accepting gifts and hospitality from contractors and external suppliers who have had contracts with the GLA.

A spokesperson for the GLA said the monitoring officer reviewed the complaint against the mayor and would not be investigating three of the four allegations.

Ms Hall said: "Whilst I welcome an investigation into the propriety of accepting these tickets, after months of asking Khan for answers, I am disappointed that the monitoring officer isn't considering the fact that the mayor declared these tickets late, initially mis-declared who donated them, that they were undervalued, or that the donor was a GLA contractor."

The Tories in the London Assembly asked the GLA's monitoring officer to probe a potential breach of the rules.

Conservative Assembly Member Susan Hall wrote to the GLA's monitoring officer Rory McKenna, claiming the mayor had appeared to "contravene" the gifts and hospitality procedure.